---
title: MDR Device Classification Explained: How to Classify Your Medical Device
description: The MDR classifies medical devices into Class I, IIa, IIb, and III by risk. Here is the step-by-step classification process and the Annex VIII rules that drive it.
authors: Tibor Zechmeister, Felix Lenhard
category: Device Classification & Conformity
primary_keyword: MDR device classification
canonical_url: https://zechmeister-solutions.com/en/blog/mdr-device-classification-explained
source: zechmeister-solutions.com
license: All rights reserved. Content may be cited with attribution and a link to the canonical URL.
---

# MDR Device Classification Explained: How to Classify Your Medical Device

*By Tibor Zechmeister (EU MDR Expert, Notified Body Lead Auditor) and Felix Lenhard.*

> **Under the EU Medical Device Regulation, every medical device is assigned to one of four classes — I, IIa, IIb, or III — based on the risk it poses to patients and users. Classification is governed by Article 51 and the twenty-two rules in Annex VIII, and it is driven by four factors: the intended purpose of the device, its duration of contact with the body, whether it is invasive and how, and whether it is active. The class determines the conformity assessment route, the level of Notified Body involvement, the clinical evidence requirements, and effectively the cost and timeline of certification. Classify wrong and every downstream decision is wrong with it.**

**By Tibor Zechmeister and Felix Lenhard. Last updated 10 April 2026.**

---

## TL;DR

- The MDR has four device classes: Class I (lowest risk), Class IIa, Class IIb, and Class III (highest risk). The class is determined by Annex VIII classification rules, not chosen by the manufacturer.
- Classification is governed by Article 51 of Regulation (EU) 2017/745 and the twenty-two rules laid out in Annex VIII. The rules apply based on the device's intended purpose under Article 2(12).
- The four drivers of classification are duration of use (transient, short-term, long-term), degree of invasiveness, whether the device is active, and whether any special rules apply (for example, devices incorporating medicinal substances, devices using nanomaterials, or software).
- Software as a medical device is classified under Rule 11, which in most cases pushes diagnostic and therapeutic decision-support software to Class IIa or higher — a change that caught many SaMD companies off guard under the MDR.
- The class determines the conformity assessment procedure under Article 52. Class I devices (non-sterile, non-measuring, non-reusable surgical) can self-declare. Everything else requires a Notified Body.
- Classification is sometimes disputed. Where the rules allow judgment, a defensible position backed by evidence can mean the difference between a Class I and a Class IIa path — and the corresponding difference in cost, time, and clinical evidence obligations.
- If the intended purpose is not yet stable, classification is premature. Fix the intended purpose first; classify second; plan the conformity assessment third.

---

## Why classification is the most consequential decision in your MDR project

Classification is the hinge. Every other regulatory decision — the QMS scope, the clinical evidence strategy, the technical documentation depth, the need for a Notified Body, the cost, the timeline, even whether the device needs a certificate at all — flows downstream from the class. Get the class wrong and you build the wrong project. Build the wrong project and you either over-invest and run out of runway before you ship, or under-invest and fail the Notified Body audit when it finally comes.

The founders we work with typically arrive with a rough guess. "We think we're Class IIa." "The consultant said Class I." "Our competitor is IIb, so we must be too." None of these are classifications. A classification is a specific rule from Annex VIII, applied to a specific intended purpose, producing a specific class, documented in a specific way, and defensible to a Notified Body auditor. Anything less is a placeholder.

This post is the hub for everything else in the classification cluster on this blog. It walks through the four classes, the structure of Annex VIII, the rule families, the special case of software under Rule 11, and the decision sequence a founder can follow to produce a defensible classification. The spoke posts linked at the end go deeper on each topic. Start here, then follow the links that match your device.

## The four device classes under the MDR

The MDR divides medical devices into four classes by risk. The exact definitions and the full list of rules live in Annex VIII, but the short version looks like this.

**Class I — lowest risk.** Devices that pose minimal risk to the patient or user. Most Class I devices can be self-certified: the manufacturer declares conformity without a Notified Body certificate for the device itself. Three Class I sub-categories do require Notified Body involvement for specific aspects: Class I sterile (Is), Class I with measuring function (Im), and Class I reusable surgical instruments (Ir). A wooden tongue depressor is Class I. A non-sterile elastic bandage is Class I. A simple manual wheelchair is Class I.

**Class IIa — medium risk.** Devices with a moderate risk profile. A Notified Body must assess the technical documentation on a representative basis. Conformity assessment routes are defined in Article 52. Most short-term invasive devices, most active devices that administer or exchange energy, and most software that provides information used for diagnostic or therapeutic decisions fall here. Contact lenses are typically Class IIa. Hearing aids are typically Class IIa. Most diagnostic imaging software is Class IIa or higher.

**Class IIb — higher risk.** Devices with a significant risk profile, usually because they are long-term invasive, active therapeutic with potential for harm, or involve a critical body function. A Notified Body assesses the technical documentation and the QMS. Infusion pumps are typically Class IIb. Ventilators are typically Class IIb. Long-term surgical sutures are typically Class IIb.

**Class III — highest risk.** Devices with the highest risk profile: implantables intended for long-term use, devices incorporating medicinal substances with ancillary action, devices used in direct contact with the central nervous or central circulatory system, and others specifically listed in Annex VIII. Class III devices face the most rigorous conformity assessment, including mandatory clinical investigations in most cases. Heart valves are Class III. Hip implants are Class III. Most active implantable devices are Class III.

The class is not a label the founder picks. It is the output of applying Annex VIII to the device's intended purpose. If two different rules point to two different classes for the same device, the higher class applies — this is the "highest class wins" principle from Annex VIII.

## How Annex VIII is structured

Annex VIII of the MDR is the rulebook. It has three parts: definitions, implementing rules, and classification rules. Most of the time, the founder is reading the third part — the twenty-two classification rules — but the first two parts determine how those rules are applied.

**Definitions.** Annex VIII defines the terms the rules use: duration of use (transient, short-term, long-term), invasive device, surgically invasive device, implantable device, active device, active therapeutic device, active device for diagnosis and monitoring, central circulatory system, central nervous system, and others. These definitions are not casual. "Transient" under the MDR means normally intended for continuous use for less than 60 minutes. "Short-term" means 60 minutes to 30 days. "Long-term" means more than 30 days. If a founder uses the word "long-term" in a commercial sense but the device is only used for two hours, Annex VIII disagrees.

**Implementing rules.** The second part of Annex VIII is often overlooked but structurally important. It contains the principles that govern how the rules are applied: the intended purpose determines classification, accessories are classified on their own, software driving or influencing a device falls in the same class as the device, the highest applicable class wins when multiple rules apply, and so on. Skip these implementing rules and the classification will be wrong even if the rule selection is right.

**Classification rules (1-22).** The twenty-two rules are grouped into families by device type. Rules 1-4 cover non-invasive devices. Rules 5-8 cover invasive devices. Rules 9-13 cover active devices. Rules 14-22 are special rules for specific categories — devices incorporating medicinal substances, devices for contraception or prevention of sexually transmitted diseases, devices for disinfecting or sterilising, devices using non-viable biological materials, devices using nanomaterials, and others. Rule 11 — the software rule — sits within the active device family and is the rule that changed SaMD classification most dramatically under the MDR.

MDCG 2021-24 (Guidance on classification of medical devices, October 2021) is the authoritative interpretation guide for Annex VIII. If you are classifying a device and the Annex VIII text alone does not resolve it, MDCG 2021-24 is the next stop. The Borderline and Classification Manual (Version 4, September 2025) contains case-by-case decisions from the Borderline and Classification Working Group on specific products — when a competitor or similar device appears in the manual, that decision is strong precedent.

## The main rule families

You do not need to read all twenty-two rules in order. You need to find the family that applies to your device and read the rules in that family carefully.

### Non-invasive devices (Rules 1-4)

Rule 1 is the default for non-invasive devices: Class I unless another rule applies. Rule 2 covers non-invasive devices intended for channelling or storing substances or gases for later infusion, administration, or introduction into the body — these range from Class I to Class IIa depending on what the substance is and how the device interacts with it. Rule 3 covers non-invasive devices intended to modify the biological or chemical composition of human tissues, cells, or body liquids — typically Class IIb, but can be Class IIa if the modification is limited. Rule 4 covers non-invasive devices in contact with injured skin or mucous membranes, with class depending on the nature of the wound and the intended purpose.

### Invasive devices other than surgically invasive (Rules 5)

Rule 5 covers devices invasive with respect to body orifices (mouth, nose, ear, rectum, vagina, urethra) that are not surgically invasive. Class depends on duration: transient is Class I, short-term is Class IIa (with exceptions for oral cavity or ear canal), long-term is Class IIb.

### Surgically invasive devices (Rules 6-8)

Rule 6 covers transient surgically invasive devices — Class IIa by default, with specific upgrades for devices in contact with the heart, central circulatory system, or central nervous system (Class III), and for reusable surgical instruments (Class I reusable — the Ir subcategory). Rule 7 covers short-term surgically invasive devices. Rule 8 covers long-term surgically invasive and implantable devices, where the default starts at Class IIb and moves to Class III for devices in contact with the heart, central circulatory system, central nervous system, spinal column, or intended to be absorbed or to undergo chemical change in the body. Rule 8 is where most implants live.

### Active devices (Rules 9-13)

Active devices are powered by a source of energy other than the human body or gravity. Rule 9 covers active therapeutic devices intended to administer or exchange energy — typically Class IIa, escalating to Class IIb where the administration is potentially hazardous. Rule 10 covers active devices intended for diagnosis and monitoring, with class depending on the nature of the monitoring. Rule 11 covers software. Rule 12 covers active devices intended to administer or remove medicinal products, body liquids, or other substances. Rule 13 covers all other active devices — Class I by default.

### Special rules (Rules 14-22)

The special rules exist because some device categories do not fit cleanly into the invasive/active classification but still need specific risk treatment. Devices incorporating medicinal substances with ancillary action are Class III. Devices incorporating non-viable animal or human tissues or cells are Class III. Devices for contraception or prevention of STDs are typically Class IIb or III. Devices specifically intended for disinfecting, cleaning, or sterilising other medical devices have their own classification path. Devices using nanomaterials have a classification tied to the potential for internal exposure. Devices used for apheresis are Class III. Devices composed of substances introduced via a body orifice or applied to the skin and absorbed or dispersed in the body are classified specifically by Rule 21. Devices incorporating or consisting of active implantable devices or accessories are Class III.

The full text of each rule is in Annex VIII. Do not work from paraphrases — the paraphrases in any blog post, including this one, exist to orient you. The classification itself must be made against the actual text of the rule that applies.

## How intended purpose drives classification

Classification cannot be done without a stable intended purpose. This is the point that catches the most founders. The intended purpose is defined in Article 2(12) of Regulation (EU) 2017/745 as "the use for which a device is intended according to the data supplied by the manufacturer on the label, in the instructions for use, or in promotional or sales materials or statements, and as specified by the manufacturer in the clinical evaluation." Read that sentence carefully. The intended purpose is not a marketing statement. It is a regulatory commitment, documented across the label, the IFU, the promotional materials, and the clinical evaluation, that must be internally consistent. The Notified Body will check whether what the website says matches what the IFU says matches what the clinical evaluation covers. If they diverge, the classification is questionable.

Change the intended purpose, and the classification can change with it. We worked with a Graz-based company that had spent months building an MDR strategy for one intended purpose. A deliberate and expert-guided revision re-framed the product as a wellness device rather than a medical device — not by changing the technology or the product, but by changing the regulatory positioning. Market entry became much faster. (This works only when the underlying use genuinely is not medical. Re-framing a medical device as a wellness product to avoid the MDR is fraud. Re-framing a product that was wrongly assumed to be a medical device, when the real intended use is wellness, is correct classification.)

The Purpose Pass — a concept we cover in depth in the Subtract to Ship framework — is the discipline of working out the intended purpose first, explicitly, before classifying anything. If a founder cannot write the intended purpose in one paragraph that makes sense on the label, in the IFU, on the website, and in the clinical evaluation simultaneously, the product is not ready for classification. Fix the purpose; then classify.

## The software special case — Rule 11

Software deserves its own section because the MDR changed software classification more than most other device categories. Under the predecessor directive, a lot of software sat comfortably in Class I. Under Rule 11 of the MDR, most software that provides information used for decisions with diagnostic or therapeutic purposes, or that is intended to monitor physiological processes, is pushed to Class IIa or higher.

The actual Rule 11 text distinguishes software intended to provide information for diagnostic or therapeutic decisions (Class IIa, with escalation to Class IIb where the decisions could cause serious deterioration of health or surgical intervention, and to Class III where the decisions could cause death or irreversible deterioration of health) from software intended to monitor physiological processes (Class IIa, with escalation to Class IIb for monitoring vital physiological parameters where variations could result in immediate danger). Software that does not fall into either of these categories is Class I by default, but "does not fall into either" is a narrower box than most SaMD founders assume.

MDCG 2019-11 Rev.1 (June 2025) is the authoritative guidance on software qualification and classification under the MDR and IVDR. It includes decision trees and worked examples. If your product is software — standalone or embedded — read MDCG 2019-11 carefully before reading Annex VIII. The MDCG guidance will usually tell you what the qualification question is before you reach the classification question.

There is also a structural subtlety worth understanding. Software that drives or influences a hardware device falls in the same class as the hardware device under the implementing rules of Annex VIII. Standalone software is classified on its own under Rule 11. A device that is hardware plus software has to be analysed as a whole, and sometimes the hardware and software parts are disputed separately. We worked on a combined hardware-software device where the software side was clearly Class IIa, but the hardware side was disputed: was it Class I, or Class I with measurement function? The distinction mattered because measurement function triggers additional conformity assessment requirements. A careful analysis of the evidence produced a defensible argument that the hardware was Class I only, and the Notified Body accepted it. This is not gaming the rules — it is applying them correctly with supporting evidence. Where the rules allow judgment, judgment produces outcomes.

## The classification decision sequence

Here is the sequence we run in every classification project. It mirrors the structure of Annex VIII and the logic of MDCG 2021-24.

**Step 1 — Confirm it is a medical device at all.** Apply Article 2(1) of the MDR and, if needed, the Borderline Manual v4. If the product is not a medical device, classification does not apply and the MDR does not apply. This is the Purpose Pass output in practice.

**Step 2 — Write the intended purpose in one paragraph.** Use the Article 2(12) definition. Make sure the paragraph is internally consistent with the label, the IFU, the promotional materials, and the planned clinical evaluation. If it is not, fix the inconsistencies before classifying.

**Step 3 — Identify the device type.** Is it non-invasive, invasive (not surgical), surgically invasive, or active? Is it software? Does a special rule category apply (medicinal substance, biological material, nanomaterial, contraception, disinfection)? This determines the rule family.

**Step 4 — Identify the duration of use.** Transient (under 60 minutes continuous use), short-term (60 minutes to 30 days), or long-term (over 30 days)? Duration is based on intended continuous use, not total product lifetime.

**Step 5 — Apply every rule that could apply.** Read each potentially applicable rule in full, in the actual MDR text. Do not stop at the first rule that seems to fit. Multiple rules may apply. The highest class wins.

**Step 6 — Check the special rules.** Rules 14-22 override the basic families in some cases. Check whether any of them applies before finalising the class.

**Step 7 — Cross-check against MDCG 2021-24 and the Borderline Manual.** If a comparable device appears in the Borderline Manual with a specific classification decision, that decision is strong precedent.

**Step 8 — Document the classification with the specific rule citation.** The output is not "Class IIa." The output is "Class IIa by Annex VIII, Rule X, paragraph Y, based on intended purpose [paragraph], duration [transient/short-term/long-term], and characterisation as [invasive/active/software/other]." That is a defensible classification. Anything less is a guess.

**Step 9 — Select the conformity assessment route.** Article 52 of the MDR and the corresponding annexes (IX, X, XI) specify the conformity assessment routes available for each class. The class constrains the routes, but within each class there are usually options. The choice has significant cost and time implications.

## Common classification traps startups fall into

**Classifying against the prototype rather than the intended purpose.** The intended purpose is a regulatory commitment. The prototype is an early engineering artifact. Classify against the former, not the latter.

**Taking a competitor's classification as given.** A competitor may have classified wrongly, or may have a slightly different intended purpose that justifies a different class, or may be operating under the legacy MDD certificate during the transitional period. Competitor classifications are data points, not conclusions.

**Missing the implementing rules.** The "highest class wins" principle, the accessory classification rule, and the software-driving-hardware rule are all easy to miss if you jump straight to Rules 1-22. The implementing rules come first for a reason.

**Assuming Class I for software because the MDD assumption carried over.** It often does not. Rule 11 pushes most diagnostic and therapeutic decision-support software to Class IIa or higher. Re-classify under the MDR; do not inherit from the MDD.

**Confusing intended purpose with claimed indications.** Indications are a subset of intended purpose. Intended purpose is broader and includes who uses the device, where, on whom, for what, for how long, and with what expected outcome. All of this must be consistent.

**Treating duration of use as product lifetime.** A device used for 30 minutes per session, multiple times over two years, is transient. A device continuously worn for 35 days is long-term. Duration is about continuous use, not calendar time.

**Skipping the special rules.** Rules 14-22 are easy to miss because they do not follow the invasive/active structure. Read them. At least one of them often applies in ways founders do not expect.

## What the class implies for conformity assessment

The class determines the conformity assessment route under Article 52. The routes vary in rigour, cost, and time.

**Class I (non-sterile, non-measuring, non-reusable surgical).** Self-declaration. The manufacturer prepares the technical documentation, draws up the EU declaration of conformity, and applies the CE marking. No Notified Body certificate for the device itself. The QMS still has to comply with the relevant parts of the MDR, but there is no Notified Body audit of the QMS for this sub-class.

**Class I sterile, Class I measuring, Class I reusable surgical instruments (Is, Im, Ir).** A Notified Body is involved, but only for the specific aspect — sterility, metrological aspects, or reprocessing — not for the full QMS or technical documentation review.

**Class IIa.** A Notified Body audits the QMS and assesses the technical documentation on a representative basis across the devices covered by the certificate. Annex IX (full QMS plus technical documentation assessment) or Annex XI (product conformity verification) are the main routes.

**Class IIb.** A Notified Body audits the QMS and assesses the technical documentation, typically with broader and deeper sampling than Class IIa. Implantable Class IIb devices have additional requirements.

**Class III.** Full QMS audit, full technical documentation assessment for each device or device group, and mandatory clinical investigations in most cases, subject to the specific exemptions in Article 61(4)-(6) and the guidance in MDCG 2023-7. Class III is the most rigorous path and carries the highest cost and longest timeline.

The gap between Class I and Class IIa is the largest single cost step in the MDR conformity assessment landscape, because it is where Notified Body involvement begins. The gap between Class IIa and Class IIb is smaller in principle but significant in practice because the depth of assessment changes. The gap between Class IIb and Class III is driven mostly by clinical evidence requirements — a Class III device typically needs clinical investigations that a Class IIb device often does not.

Understanding these gaps is why classification is not just a regulatory checkbox. It is the input that determines your burn rate for the next twelve to twenty-four months.

## The Subtract to Ship angle on classification

The Subtract to Ship framework, which we cover in detail in the [Subtract to Ship framework for MDR compliance](/blog/subtract-to-ship-framework-mdr) post, treats classification as the second of four passes — after the Purpose Pass and before the Evidence Pass. The key discipline is finding the lowest defensible classification. Not the lowest classification a founder wishes for. Not the highest classification a cautious consultant recommends. The lowest defensible one, backed by a specific Annex VIII rule, a specific intended purpose, and a specific argument a Notified Body will accept.

Subtracting in the classification pass means cutting every activity that would only be required at a higher class than the one that actually applies. Over-scoping the QMS, over-scoping the clinical evidence plan, over-scoping the technical documentation depth — all of these are common, all of them drain runway, and all of them are avoidable if the class is known and the requirements are read by class rather than guessed.

Under-scoping is also possible and more dangerous. A founder who talks themselves into Class I to avoid a Notified Body, when the rules genuinely point to Class IIa, is not subtracting. They are hiding from the truth. The Notified Body will find them eventually. Subtract to Ship is not about avoiding the class that applies. It is about not paying for the class that does not apply.

## Reality Check — Where do you stand on classification?

1. Can you write your device's intended purpose in one paragraph that is consistent with what your website, label, IFU, and clinical evaluation will all say?
2. Have you identified the specific Annex VIII rule that applies to your device, by number, and can you quote the rule text from the actual MDR?
3. Have you checked every other potentially applicable rule, not just the first one that fits?
4. Have you checked the Annex VIII implementing rules — the highest-class-wins principle, the accessory rule, the software-driving-hardware rule?
5. For software, have you read MDCG 2019-11 Rev.1 (June 2025) and applied Rule 11, rather than inheriting a legacy assumption?
6. Have you cross-checked your classification against MDCG 2021-24 and the Borderline Manual v4?
7. Have you characterised the duration of use correctly — continuous intended use, not calendar lifetime?
8. Have you identified the conformity assessment route under Article 52 that follows from the class, and do you understand what it will cost?
9. If a Notified Body auditor walked in tomorrow and asked why your device is the class you say it is, could you answer in one paragraph with a specific rule citation?
10. Have you documented the classification with enough rigor that a future team member, or a future consultant, could follow the reasoning without re-doing the work?

## Frequently Asked Questions

**What determines the class of a medical device under the MDR?**
The class is determined by the twenty-two classification rules in Annex VIII of Regulation (EU) 2017/745, applied to the device's intended purpose. The main drivers are whether the device is invasive (and how), whether it is active, how long it is in contact with the body, and whether any special rules apply. Article 51 of the MDR sets the classification framework; Annex VIII contains the actual rules. MDCG 2021-24 (October 2021) is the authoritative interpretation guide.

**Who classifies a medical device — the manufacturer or the Notified Body?**
The manufacturer classifies the device. The Notified Body reviews and either accepts or disputes the classification during the conformity assessment. If the Notified Body disagrees, they can require reclassification. Classification is the manufacturer's responsibility and the manufacturer's risk. A wrong classification that is later overturned can invalidate months or years of regulatory work.

**Is software always Class IIa or higher under the MDR?**
No, but often. Rule 11 of Annex VIII pushes most software that provides information used for diagnostic or therapeutic decisions, or that monitors physiological processes, to Class IIa or higher. Software that does not fall into either category can still be Class I. MDCG 2019-11 Rev.1 (June 2025) is the guidance document that walks through software qualification and classification with decision trees and examples. Read it before classifying any software product under the MDR.

**Can I change the class of my device by changing the intended purpose?**
Sometimes, yes, if the change reflects a genuine difference in how the device is used. We have worked with companies where a deliberate revision of the intended purpose correctly re-classified the product or moved it outside the MDR scope. This only works when the underlying use genuinely matches the new intended purpose. Re-framing a medical device as a wellness product to avoid the MDR is fraud. Correctly classifying a product whose real use is wellness as a wellness product is compliance.

**What is the difference between Class IIa and Class IIb for Notified Body involvement?**
Both require a Notified Body, and both require a QMS audit and technical documentation assessment. Class IIb assessments are typically broader and deeper in scope, particularly for implantables. The specific conformity assessment routes are defined in Article 52 and Annexes IX, X, and XI. The cost and time differences between IIa and IIb are significant in practice, though smaller than the gap between Class I and Class IIa.

**Do I need a Notified Body for a Class I device?**
For a standard Class I device (non-sterile, non-measuring, non-reusable surgical), no. The manufacturer self-declares conformity. For Class I sterile (Is), Class I with measuring function (Im), and Class I reusable surgical instruments (Ir), a Notified Body is involved for those specific aspects only. The full QMS audit and full technical documentation assessment begin at Class IIa.

**How often should I re-check my device's classification?**
Whenever the intended purpose changes, whenever the device's physical characteristics change, whenever a new indication is added, whenever new MDCG guidance is published that affects your rule, and before any major regulatory milestone (Notified Body application, clinical investigation submission, significant design change). Classification is not a one-time decision — it is a live commitment that has to stay aligned with the product.

## Related reading

- [What is the EU Medical Device Regulation?](/blog/what-is-eu-mdr) — the fundamentals post on the MDR itself.
- [MDR Article 2: Definitions That Matter Most](/blog/mdr-article-2-definitions) — the definitions layer that every classification decision depends on.
- [What Is a Medical Device Under MDR?](/blog/what-is-medical-device-under-mdr) — the qualification question that has to be answered before classification.
- [When to Start MDR Regulatory Work](/blog/when-to-start-mdr-regulatory-work) — why classification should be fixed early, not late.
- [The Subtract to Ship Framework for MDR Compliance](/blog/subtract-to-ship-framework-mdr) — the methodology that treats classification as the second of four passes.
- [MDR Annex VIII Classification Rules: Complete Guide](/blog/mdr-annex-viii-classification-rules-complete-guide) — the deep dive on all twenty-two rules, rule by rule.
- [Class I Medical Devices Under MDR](/blog/class-i-medical-devices-under-mdr) — the full spoke on what Class I means in practice, including Is, Im, and Ir.
- [Class IIa Medical Devices Under MDR](/blog/class-iia-medical-devices-under-mdr) — the full spoke on Class IIa, including conformity assessment routes.
- [Class IIb Medical Devices Under MDR](/blog/class-iib-medical-devices-under-mdr) — the full spoke on Class IIb, including implantable specifics.
- [Class III Medical Devices Under MDR](/blog/class-iii-medical-devices-under-mdr) — the full spoke on Class III, including mandatory clinical investigations.
- [MDR Classification Rule 11: Software](/blog/mdr-classification-rule-11-software) — the deep dive on Rule 11 for SaMD.
- [Intended Purpose vs. Intended Use Under MDR](/blog/intended-purpose-vs-intended-use-mdr) — the precise meaning of the terms that drive classification.
- [Seven Classification Mistakes Startups Make Under the MDR](/blog/7-classification-mistakes-startups-make-under-mdr) — the failure modes to avoid.

## Sources

1. Regulation (EU) 2017/745 of the European Parliament and of the Council of 5 April 2017 on medical devices, Article 2(1) (definition of medical device), Article 2(12) (intended purpose), Article 51 (classification), Article 52 (conformity assessment procedures), Annex VIII (classification rules, including definitions, implementing rules, and Rules 1-22), Annex IX, Annex X, Annex XI (conformity assessment routes). Official Journal L 117, 5.5.2017.
2. MDCG 2021-24 — Guidance on classification of medical devices, October 2021.
3. MDCG 2019-11 Rev.1 — Guidance on Qualification and Classification of Software in Regulation (EU) 2017/745 — MDR and Regulation (EU) 2017/746 — IVDR, October 2019, Revision 1 June 2025.
4. Manual on borderline and classification for medical devices under Regulation (EU) 2017/745 and Regulation (EU) 2017/746, Version 4, September 2025 (Borderline and Classification Working Group of the MDCG).
5. EN ISO 13485:2016 + A11:2021 — Medical devices — Quality management systems — Requirements for regulatory purposes.
6. EN 62304:2006 + A1:2015 — Medical device software — Software life-cycle processes.

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*This post is the pillar for the Device Classification & Conformity Assessment series in the Subtract to Ship: MDR blog. Authored by Felix Lenhard and Tibor Zechmeister. Every spoke post in the classification cluster links back here. If the complexity of classifying your specific device exceeds what a blog post can cover — and for most startups, it will, because every device is different — a classification working session with a sparring partner who has done this across fifty-plus certifications is usually the fastest path to a defensible answer.*

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*This post is part of the [Device Classification & Conformity](https://zechmeister-solutions.com/en/blog/category/classification) cluster in the [Subtract to Ship: MDR Blog](https://zechmeister-solutions.com/en/blog). For EU MDR certification consulting, see [zechmeister-solutions.com](https://zechmeister-solutions.com).*