ISO 9001 vs ISO 9000: What Each One Is

In short: ISO 9001 vs ISO 9000 confuses almost everyone, and the answer is simple. ISO 9000 is the background document: the principles and vocabulary of quality management. ISO 9001 is the one with the actual requirements, and the only one of the two you can be certified to. If a customer asks for a certificate, they mean ISO 9001, and our ISO 9001 templates help you build a system that wins that work.

This one tripped me up early on too, so don't feel daft if the near-identical numbers have you confused. It's simpler than it looks. When a customer asks for your certificate, they mean ISO 9001, every time. ISO 9000 is just the background reading. Let me clear it up in a minute flat, one business owner to another, so you can stop worrying about the wrong number and get on with the one that actually wins you work.

If you have been trying to work out the difference between ISO 9001 and ISO 9000, you are not being slow. The names are almost identical and the way they are thrown around makes it worse. Here is the plain answer, with the key difference up front in a table.

ISO 9000 vs ISO 9001 at a glance

	ISO 9000	ISO 9001
What it is	The fundamentals and vocabulary of quality management: the principles and the definitions.	The actual requirements a business must meet for its quality management system.
What it is for	Background and understanding. It explains the ideas and terms the other standards use.	Doing and proving. It sets out what you have to have in place.
Can you be certified to it?	No. You cannot be certified to ISO 9000.	Yes. ISO 9001 is the one you get certified to.
Who needs it	Useful reference for anyone wanting to understand the language of quality.	Any business that wants to run to the standard or hold a certificate.

The simplest way to remember it

ISO 9000 is the glossary and the thinking. ISO 9001 is the rulebook you are actually measured against.

They are part of the same family, which is why the numbers are so close and why people mix them up. ISO 9000 explains the ideas and defines the terms. ISO 9001 takes those ideas and turns them into the specific things a business must do. When a customer, a tender or a contract asks you to be certified, it is always ISO 9001 they mean, because it is the only one of the two you can actually hold a certificate for.

So why does ISO 9000 exist at all?

It is the reference book that makes the rulebook make sense. If you read ISO 9001 and wonder what a particular term really means, or what principle sits behind a requirement, ISO 9000 is where that is spelled out. You do not need to buy or study it to get certified. Most businesses never touch it directly, because a good plain-English set of documents already translates the important bits for you.

What about ISO 9002, 9003 and 9004?

You may come across these too, so briefly: ISO 9002 and ISO 9003 were older, narrower standards that were folded into ISO 9001 years ago and no longer exist as separate certifications. ISO 9004 is a guidance document about improving performance beyond the basic requirements, and like ISO 9000 you cannot be certified to it. For almost everyone, ISO 9001 is the only number that matters.

Which one do you actually need?

ISO 9001, in almost every case. If your goal is a certificate, to win work or reassure customers, ISO 9001 is the one, full stop. ISO 9000 is background you can safely leave to one side. Do not let the near-identical names slow you down: focus on ISO 9001 and you are focusing on the right thing.

Ready to get to grips with ISO 9001 itself? Start with our plain-English guide, what ISO 9001 is, then see where you stand with the free readiness quiz.

Frequently asked questions

What is the difference between ISO 9001 and ISO 9000?

The difference is that ISO 9000 sets out the principles and vocabulary of quality management, while ISO 9001 sets out the actual requirements you must meet. ISO 9000 is the background explainer; ISO 9001 is the standard you are assessed and certified against. In everyday terms, ISO 9000 is the glossary and ISO 9001 is the rulebook.

Are ISO 9000 and ISO 9001 the same thing?

No, they are not the same, though they belong to the same family and are easily confused. ISO 9000 explains the concepts and defines the terms; ISO 9001 contains the requirements a business has to satisfy. Only ISO 9001 can be certified, so when people loosely say "ISO 9000" they usually mean ISO 9001.

Can you be certified to ISO 9000?

No, you cannot be certified to ISO 9000, because it is a reference document of principles and vocabulary rather than a set of requirements. Certification is only possible against ISO 9001, which sets out the specific things your quality management system must do. If a customer asks for a certificate, they mean ISO 9001.

Which is better, ISO 9000 or ISO 9001?

Neither is better; they do different jobs, but ISO 9001 is the one you need for a certificate. ISO 9000 helps you understand the language and ideas, while ISO 9001 is the standard you actually implement and get assessed against. For almost every business, ISO 9001 is the one that matters in practice.

Is ISO 9002 still a thing?

No, ISO 9002 no longer exists as a separate standard; it and ISO 9003 were older, narrower standards that were merged into ISO 9001 years ago. Today there is a single requirements standard, ISO 9001, which covers what those older numbers used to. If you see ISO 9002 referenced, it is out of date.

Now the names make sense, focus on the one that counts. See how ready you are for ISO 9001 with the free readiness quiz, no email required.

About the author

Written by Mike Armstrong, senior ISO consultant, former company director, and founder of Plain Standards. In over 30 years running companies at director level, Mike built his own management systems to drive profit long before he adopted ISO 9001, so he comes at this from the owner's side, not the auditor's. Plain Standards helps small and medium sized businesses get ISO certified without a consultant.