Certification is a body auditing your company and issuing a certificate that your management system meets a standard like ISO 9001. Accreditation is a higher body assessing that certification body's competence. Put simply: certification bodies certify companies; accreditation bodies accredit the certifiers.
The two words get used interchangeably, and on a supplier questionnaire that mix-up can cost you. A certificate on a wall proves someone signed it. Whether that someone was themselves checked by an independent authority is the difference between a certificate a customer accepts and one they hand back. This is the chain of trust behind every ISO certificate, and it is worth understanding before you rely on your own or a supplier's.
What is the difference between certification and accreditation?
Certification points down at a company; accreditation points down at a certifier. When a certification body audits your plant and decides your quality management system meets ISO 9001, it certifies you and issues a certificate. When an accreditation body assesses that certification body, its auditors, its impartiality, its procedures, and decides it is competent to issue such certificates, it accredits the certifier. You are certified. Your certifier is accredited. You are never "accredited" to ISO 9001, and a certifier is never "certified" to audit; the vocabulary is not interchangeable even though people swap it constantly.
The rulebooks make the split concrete. Certification bodies for management systems work to ISO/IEC 17021-1 which sets requirements for their competence, consistency, and impartiality. Accreditation bodies work to ISO/IEC 17011 which sets the requirements for assessing and accrediting those certifiers. Two standards, two jobs, two layers.
Who certifies whom?
Trace it from the top and the layers stop blurring. A standards body such as ISO writes the standard, ISO 9001 for quality, ISO 14001 for environment, ISO 13485 for medical devices. An accreditation body assesses certifiers against ISO/IEC 17011 and grants them accreditation for specific standards and scopes. An accredited certification body then audits your company against the standard and, if you pass, issues the certificate. Your company sits at the bottom holding the paper, and every layer above it has been checked by the layer above that.
Most countries recognize one or a few national accreditation bodies. In the United States that role is filled by the ANSI National Accreditation Board (ANAB). The point of a single recognized accreditation body per economy is that certificates become comparable: a certificate accredited by a recognized body means the same thing whoever issued it.
Why does accreditation matter for a valid ISO certificate?
Because without it, "certified" only means a certifier said so, and anyone can set up as a certifier. Accreditation is the independent check that the certifier is competent and impartial, that it actually audits, does not sell certificates, and applies the standard the way everyone else does. An accredited certificate is traceable up the chain to a recognized authority; an unaccredited one traces only to the company that sold it.
This is not academic. Many customers, and most regulated supply chains, will accept only accredited certificates. If you buy a certificate from an unaccredited certifier, you may have spent real money on a document your biggest customer rejects on their supplier qualification. The same logic runs through the calibration labs that keep your measurement equipment honest: a lab that calibrates your gauges or your coordinate measuring machine is itself accredited (to ISO/IEC 17025), which is what lets you claim measurement traceability on an audit. Accreditation is the reason a stamp from a lab you have never visited is worth trusting.
How do you tell if a certificate is accredited?
Look for the accreditation body's mark, not just the certifier's logo, then confirm it in a registry. A genuine accredited certificate carries two identities: the certification body that issued it and the accreditation body that vouches for that certifier. A certificate showing only the certifier's own logo, with no accreditation mark, is either unaccredited or a self-declaration, treat it as unverified until proven otherwise.
- Read the accreditation mark. It names the accreditation body and usually a unique accreditation number for the certifier.
- Check the scope. Accreditation is granted for specific standards and industry scopes. A certifier accredited for food safety is not automatically accredited for aerospace. Confirm the scope on the certificate covers what you actually need, the same care you would take reading an AS9100 or IATF 16949 scope.
- Confirm the status in a registry. Accreditation bodies publish the certifiers they accredit, and there is a global certificate database (IAF CertSearch) for validating accredited certificates. A logo is a claim; the registry entry is the proof.
How do you verify a supplier's certificate the right way?
Do it in a fixed order so nothing gets skipped, and so the answer is a fact instead of a feeling.
- Find the accreditation mark on the certificate. No mark, no accreditation, stop and ask the supplier who accredited their certifier.
- Identify the accreditation body named in the mark and confirm it is a recognized national or international accreditation body, not another commercial logo.
- Check the scope and dates. Confirm the certified scope covers the products or sites you buy from, and that the certificate is current, not expired or suspended.
- Confirm the entry in the public registry. Look the certificate up in the accreditation body's directory or the global certificate database and match the certifier, scope, and status.
- File the evidence. Save the registry result with the supplier record so the next audit does not repeat the work. This is exactly the kind of check a quality audit checklist should force, not leave to memory.
What changed with IAF and ILAC in 2026?
The international coordination of accreditation was reorganized. For decades, two bodies knit national accreditation bodies into one recognized system: the International Accreditation Forum (IAF) for management-system and product certification, and the International Laboratory Accreditation Cooperation (ILAC) for testing and calibration labs. Their mutual-recognition arrangements are what let an accredited certificate issued in one country be trusted in another.
As of 1 January 2026, IAF and ILAC consolidated into a single international accreditation organization, Global Accreditation Cooperation, which now carries that recognition work forward under one multilateral arrangement. IAF's own site notes it ceased operations on that date and points users to the new body (IAF legacy site). For a plant, the practical takeaways are small: certificates accredited under the old arrangements remain valid, national accreditation bodies like ANAB still do the accrediting, and the chain of trust is unchanged, only the international umbrella's name is new. If your procedures cite IAF or ILAC by name, that is a wording update worth scheduling.
The standards that govern each layer
- Certification bodies auditing management systems work to ISO/IEC 17021-1:2015 which sets requirements for their competence, consistency, and impartiality.
- Accreditation bodies work to ISO/IEC 17011:2017 which specifies requirements for the competence and impartiality of bodies that accredit certifiers and labs.
- The management-system standard most companies certify to, ISO 9001:2015 is written by ISO but audited by an accredited certification body, ISO itself does not certify anyone.
Does accreditation cost more or take longer for the company?
For you, choosing an accredited certifier does not add a separate cost or step, the accreditation happens above you, between the certifier and the accreditation body. You pay the certifier for your audit and certificate as you would either way. What accredited certification "costs" you is discipline: an accredited certifier runs a real audit, so your management system has to actually work, not just look tidy for a day.
That is the right trade. The value of a certificate is entirely in whether people trust it, and trust comes from the accreditation chain, not the certificate stock. A plant that runs its quality system for real, closing corrective actions with a genuine effectiveness check keeping calibration and audit records straight, sails through an accredited audit and gets a certificate its customers accept. A plant chasing a wall decoration buys an unaccredited one and finds out its value the day a customer asks for the registry entry. The same trend-and-record visibility Harmony's quality intelligence gives a floor team is what makes an accredited audit a formality instead of a fire drill; see our CLS case study for how that looks in practice.