---
title: FDA Device Classification: Class I, II, and III Explained for EU Startups
description: FDA classifies devices as Class I, II, or III by risk and pathway. Here is how the FDA classification compares to MDR for EU founders considering US entry.
authors: Tibor Zechmeister, Felix Lenhard
category: FDA & International Market Access
primary_keyword: FDA device classification EU startups
canonical_url: https://zechmeister-solutions.com/en/blog/fda-device-classification-eu-startups
source: zechmeister-solutions.com
license: All rights reserved. Content may be cited with attribution and a link to the canonical URL.
---

# FDA Device Classification: Class I, II, and III Explained for EU Startups

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

> **The FDA classifies medical devices into Class I, Class II, and Class III based on the level of regulatory control needed to provide reasonable assurance of safety and effectiveness. Class I is the lowest risk and is mostly subject to general controls. Class II usually needs general controls plus special controls and typically goes through a 510(k). Class III is the highest risk and generally requires Premarket Approval (PMA). Unlike MDR Article 51 and Annex VIII, where the manufacturer applies 22 rules to the device, the FDA assigns classes at the device-type level through its classification database. A device can be MDR Class IIa and FDA Class II, or MDR Class IIa and FDA Class III, and every other combination. EU founders cannot assume the two classifications map across.**

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

---

## TL;DR

- The FDA uses three device classes — Class I, Class II, Class III — defined by the level of regulatory control needed, not by a rule-based algorithm applied by the manufacturer.
- Class I is lowest risk, usually cleared through general controls and often 510(k)-exempt. Class II is the middle tier, usually reaches the market through a 510(k). Class III is the highest risk and usually requires PMA.
- Classification is assigned at the device-type level through the FDA classification database, keyed to regulation numbers and three-letter product codes. You do not run the classification rules yourself — you match your device to an existing type.
- MDR classification under Article 51 and Annex VIII and FDA classification are conceptually related but structurally different. The same device can land in different classes under each system, and software is the most common mismatch.
- For EU founders, the practical task is not "translate my MDR class to FDA" but "find the FDA product code and regulation that matches my device and read what pathway it demands."

---

## The moment this matters

A Vienna-based startup came to a first meeting with a crisp MDR classification already locked in. Class IIa under Annex VIII Rule 11 for the software component, Class I for a small accessory. They had done the work carefully, with a Notified Body in conversation, and they were proud of how clean the file looked. The investor deck included a US launch plan. When the US launch plan was poked at, the team had written a single line: "Expected FDA Class II, 510(k) pathway." No product code. No predicate. No confirmation from anyone who worked inside the FDA system.

The question that came back was simple. Which FDA regulation number and product code does your device map to? The founders did not know. When the mapping was eventually done with a US specialist, the device landed in an FDA product code that had historically gone through De Novo, not a standard 510(k), because there was no clean predicate in the classification database. The pathway assumption in the deck was wrong. Not catastrophically wrong — the De Novo route was available and workable — but wrong enough that the US timeline needed a full rework and the investor conversation needed a correction.

This pattern repeats. EU founders are trained by the MDR to think about classification as something you derive from the rules in Annex VIII. The FDA system does not work that way, and the first surprise of US market access is usually the shape of the classification question itself.

## FDA Class I at the general framing level

FDA Class I is the lowest-risk tier. These are devices for which general controls are considered sufficient to provide reasonable assurance of safety and effectiveness. General controls include basic requirements that apply to all devices — registration, listing, labelling, good manufacturing practice, and the general prohibition against adulterated or misbranded devices.

A large share of Class I devices are exempt from premarket notification (510(k)-exempt), meaning the manufacturer does not need to submit a premarket filing to the FDA before marketing, though they still must comply with the general controls and register the establishment and list the device. The exemptions are listed by regulation number in the FDA classification database.

Typical Class I examples at the general framing level include simple manual surgical instruments, examination gloves, most tongue depressors, basic bandages, and similar low-risk products. Specific classification of any particular device depends on the exact product code it maps to, not on the general category.

## FDA Class II at the general framing level

FDA Class II covers devices for which general controls alone are not sufficient and special controls are needed. Special controls can include performance standards, post-market surveillance requirements, patient registries, specific labelling requirements, and guidance documents that set out how the class of device must be evaluated.

The great majority of Class II devices reach the US market through a 510(k) premarket notification demonstrating substantial equivalence to a legally marketed predicate. A minority of Class II device types are 510(k)-exempt, and a smaller number have specific carve-outs in their classification regulation.

Class II is where most commercially significant MedTech devices live, and it is where most EU founders expect their device to land. Examples at the general framing level include infusion pumps, many imaging systems, many software-based diagnostic aids, and a very wide range of diagnostic and therapeutic equipment. The specifics always come from the product code.

## FDA Class III at the general framing level

FDA Class III covers devices that support or sustain human life, are of substantial importance in preventing impairment of human health, or present a potential unreasonable risk of illness or injury. These devices require Premarket Approval (PMA), which is the FDA's most rigorous device review process and typically involves substantial clinical evidence, extensive manufacturing review, and often one or more clinical investigations.

Class III examples at the general framing level include implantable pacemakers, heart valves, certain high-risk implants, and some novel technologies where the safety profile has not yet been established. PMA is structurally closest to a Class III MDR conformity assessment under Annex IX in terms of scope and rigor, though the specific evidence expectations on the two sides are not identical.

## The pathway implications of each class

The classification determines the pathway in a predictable but not absolute way.

Class I devices are either 510(k)-exempt (the majority) or subject to 510(k) (the minority). The exempt ones go directly to market subject to general controls, establishment registration, and device listing.

Class II devices are usually subject to 510(k) premarket notification. A minority are exempt. A very small number have specific PMA requirements inherited from historical classification decisions.

Class III devices are usually subject to PMA. A historical subset of Class III devices still sit in the 510(k) framework as a legacy of the pre-1976 classification system, though the FDA has been systematically moving these into PMA over time.

For novel devices of low to moderate risk that do not fit any existing classification — meaning there is no product code and no predicate — the De Novo pathway allows the applicant to request classification into Class I or Class II with appropriate special controls. De Novo is the pathway EU founders of genuinely new device categories often need, and it is the most common place where the "my MDR class maps to FDA Class II" assumption falls apart.

## How FDA classification compares to MDR Class I, IIa, IIb, III

The MDR and the FDA both use risk-based classification, but the mechanics are different.

Under MDR Article 51 and Annex VIII, the manufacturer applies 22 classification rules to the specific device. The rules consider duration of contact, invasiveness, whether the device is active, whether it incorporates a medicinal product, software function, and other characteristics. The outcome is one of four classes — Class I, Class IIa, Class IIb, or Class III. Guidance on applying the rules lives in MDCG 2021-24. The manufacturer's classification is then reviewed by the Notified Body during conformity assessment (except for Class I non-sterile non-measuring non-reusable-surgical devices, which self-certify).

Under the FDA framework, classification is assigned at the device-type level in a central FDA classification database. Each device type has a regulation number in the Code of Federal Regulations and a three-letter product code. The manufacturer's job is to identify which regulation and product code their device belongs to — matching by intended use and technological characteristics — and then read off the class and the pathway. Novel devices without a matching entry use De Novo.

The conceptual difference matters. MDR classification is an algorithmic derivation you perform; FDA classification is a database lookup you perform against historical agency decisions. Both are risk-based, but the surface-level task the manufacturer does is not the same.

The numerical labels also do not map one-to-one:

- MDR Class I ≠ FDA Class I in any reliable way. Some MDR Class I devices are FDA Class I, many are FDA Class II, and some software-adjacent ones are higher.
- MDR Class IIa ≠ FDA Class II. They often coincide, but not always. Software classified IIa under MDR Annex VIII Rule 11 can land in FDA Class II or FDA Class III depending on the intended use and the existing FDA product code landscape.
- MDR Class IIb is a category the FDA does not have at all. MDR Class IIb devices map to FDA Class II or FDA Class III depending on the specific device.
- MDR Class III ≈ FDA Class III in intent, though the specific list of devices in each is not identical.

The honest framing for founders is: treat the two classifications as independent. Do the MDR classification under Annex VIII. Do the FDA classification by database lookup or De Novo analysis. Compare the results after, not before.

## Where the same device lands differently

Software is the most common place where MDR and FDA classifications diverge.

MDR Annex VIII Rule 11 pushes a large category of decision-support and diagnostic software into Class IIa or higher, with some categories landing in Class IIb or Class III depending on the severity of the information the software drives. The rule is written broadly, and the interpretation has been reinforced by MDCG 2019-11.

The FDA approaches software as a medical device through a different lens: historical product codes, Software as a Medical Device (SaMD) risk framing partly aligned with IMDRF guidance, and specific guidance documents on clinical decision support software and related topics. A software that is MDR Class IIa under Rule 11 may sit in an FDA product code that has historically gone through 510(k) with minimal clinical data, or in a product code that demands extensive performance testing, or in no existing product code at all (triggering De Novo). None of this is predictable from the MDR classification alone.

Measurement devices also frequently diverge. Diagnostic devices where the measurement function matters under MDR (triggering Notified Body involvement for Class Is with measuring function) may land in an FDA class where the pathway looks quite different. Accessories, combination products, and devices where the intended purpose crosses into drug-delivery territory can diverge in either direction.

The general rule for founders is: do not assume. Look up the product code.

## Common founder confusions

- Assuming MDR class translates to FDA class. It does not, except by coincidence.
- Assuming "Class II = 510(k)" always holds. Usually it does, but there are Class II 510(k)-exempt categories and Class II PMA legacy categories.
- Assuming the 510(k) database lookup is a formality. Picking the product code is a strategic decision that affects pathway, predicates, and submission scope.
- Assuming De Novo is a fallback for "when I do not want to do PMA." De Novo is a specific pathway for novel low-to-moderate-risk devices without a predicate. Class III-level risk does not qualify.
- Assuming clinical data generated for MDR will automatically satisfy FDA Class II or Class III expectations. Sometimes yes, often no, always a specialist question.
- Assuming the FDA classification database is self-explanatory for a first-time founder. It is navigable but not friendly, and the cost of picking the wrong product code is months of wasted work.

## The Subtract to Ship angle on FDA classification work

The Subtract to Ship approach to FDA classification is the same discipline applied to MDR: do the work that ties directly to an obligation, remove the work that does not, and get expert help at the leverage points.

For FDA classification specifically, the high-leverage activity is the product code lookup and the pathway determination — done once, properly, with a US regulatory specialist who works inside the system. The low-leverage activities are speculation from EU founders about "probably Class II" and self-taught database crawling that burns weeks and produces a fragile answer.

The subtraction move is to resist the temptation to do the classification yourself to save the specialist fee. The specialist fee is small compared to the cost of a wrong product code carried forward into a 510(k) that fails, or a De Novo that never needed to be De Novo, or a PMA scoped for the wrong risk profile. Subtract the DIY classification attempt. Add the one meeting with the specialist. Keep the MDR classification work on the EU side where your existing expertise lives. That is the shape of a dual-market Subtract to Ship plan on the classification question specifically. For the foundational framework see [The Subtract to Ship framework for MDR](/blog/subtract-to-ship-framework-mdr).

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

1. Do you know the FDA product code (three letters) and the regulation number (21 CFR Part 8XX) that your device is likely to map to?
2. If you do not know the product code, have you scheduled a conversation with a US regulatory specialist to determine it?
3. Have you confirmed whether a predicate device exists in the same product code, or whether you may need De Novo?
4. Is your MDR classification under Annex VIII documented in a way that allows a US specialist to understand the intended use without re-reading the full technical file?
5. Have you verified that your indications for use statement (the FDA equivalent of intended purpose) is consistent with what you plan to submit to the Notified Body for CE?
6. Are you aware that a single device can legitimately land in different classes under MDR and FDA, and is your business plan resilient to that outcome?
7. If your device is software, have you separately considered FDA classification and MDR Annex VIII Rule 11, rather than assuming they produce the same class?

Three or fewer confident answers means the classification question is not resolved yet and any US pathway plan built on it is speculation.

## Frequently Asked Questions

**Does my MDR Class IIa device automatically become FDA Class II?**
No. FDA classification is assigned at the device-type level through the FDA classification database, keyed to product codes. A device that is MDR Class IIa under Annex VIII can map to an FDA product code that is Class II, Class III, or no existing code at all (triggering De Novo). Do the MDR classification under Annex VIII and the FDA classification by database lookup separately, then compare.

**What is an FDA product code?**
A product code is a three-letter identifier the FDA assigns to a specific device type. It sits underneath a regulation number in the Code of Federal Regulations and is the practical key for classification, 510(k) predicate searches, and adverse event database queries. Two devices with the same product code are treated as the same type for classification and pathway purposes. Picking the right product code is one of the first strategic moves in a US submission plan.

**What is the difference between 510(k)-exempt and not regulated?**
A 510(k)-exempt device is still regulated. It has a class, a product code, and obligations — including establishment registration, device listing, labelling rules, and quality system requirements. It simply does not need a premarket submission before marketing. A non-device product, by contrast, is outside FDA device regulation entirely. Do not confuse the two.

**How do I know if my device needs De Novo instead of 510(k)?**
De Novo is for novel devices of low to moderate risk that do not have a valid predicate in the FDA classification database. If no product code matches your device, or the only matching product code is Class III, you are likely looking at De Novo (or PMA if the risk is too high). This determination is made with a US regulatory specialist, not guessed from a primer.

**Is FDA Class III the same as MDR Class III?**
In intent, yes — both are the highest-risk tier and both require the most rigorous premarket review. In the specific list of devices that fall into each, there are differences. A device that is MDR Class III is likely (but not guaranteed) to be FDA Class III, and vice versa. The actual classification must be confirmed on each side independently.

**Where does this post stop and where do I need a US specialist?**
This post gives you the EU-founder mental model for how FDA classification works and how it relates to MDR. For the actual product code lookup, the pathway determination, the predicate search, and the submission planning on your specific device, work with a US regulatory specialist who operates inside the FDA system daily. The orientation belongs to this post; the execution belongs to the specialist.

## Related reading

- [MDR vs FDA: key differences every founder should know](/blog/mdr-vs-fda-key-differences-eu-us-medical-device-regulation) — the foundational side-by-side comparison.
- [Regulatory strategy for startups targeting EU and US markets](/blog/regulatory-strategy-startups-targeting-eu-us-markets) — dual-market planning in full.
- [The Subtract to Ship framework for MDR](/blog/subtract-to-ship-framework-mdr) — the methodology behind the dual-market discipline.
- [MDR device classification under Article 51 and Annex VIII](/blog/mdr-classification-article-51-annex-viii) — the EU-side classification companion.
- [FDA regulation of medical devices: a primer for EU startups](/blog/fda-regulation-medical-devices-primer-eu-startups) — the hub post for this cluster.
- [FDA vs MDR: fundamental differences](/blog/fda-vs-mdr-fundamental-differences) — the structural framing companion.
- [The 510(k) pathway for EU startups](/blog/510k-pathway-eu-startups) — predicate strategy and submission scope.
- [The De Novo pathway for EU startups](/blog/de-novo-pathway-eu-startups) — when no predicate exists.
- [The PMA pathway for EU startups](/blog/pma-pathway-eu-startups) — the high-risk device route.
- [FDA product codes and how to find yours](/blog/fda-product-codes-eu-startups) — the database lookup companion.

## Sources

1. Regulation (EU) 2017/745 of the European Parliament and of the Council of 5 April 2017 on medical devices (MDR), Article 51 and Annex VIII (classification rules). Official Journal L 117, 5.5.2017.
2. MDCG 2021-24 — Guidance on classification of medical devices, October 2021.
3. U.S. Food and Drug Administration — Center for Devices and Radiological Health (CDRH), device classification general framework and classification database. Referenced at the general framing level only.
4. U.S. Code of Federal Regulations, Title 21 — device classification regulations. Referenced at the general framing level only.

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*This post is part of the FDA & International Market Access series in the Subtract to Ship: MDR blog. Authored by Felix Lenhard and Tibor Zechmeister. A note on the limits of our expertise: Tibor's authority is in the EU MDR and the Notified Body system. For the specific FDA product code lookup, pathway determination, predicate selection, and submission work on your device, engage a US regulatory specialist who operates inside the FDA system daily. This post is the orientation; the specialist is the execution.*

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*This post is part of the [FDA & International Market Access](https://zechmeister-solutions.com/en/blog/category/fda-international) 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).*