What Is a Certificate of Conformance (CoC)?

A certificate of conformance (CoC) is a signed statement from a supplier that a shipment of parts or material meets the requirements of the purchase order, drawing and specifications. Also called a certificate of conformity, it is a declaration rather than a test report: the evidence behind it sits in inspection records and material certifications.

In short: a CoC is the supplier putting its name to "this batch is what you ordered."

What Does a Certificate of Conformance Include?

There is no single universal form, but a usable CoC identifies exactly what it covers and what it is certifying against:

Supplier name, customer name and purchase order or contract number
Part number and drawing revision, plus the specifications that apply
Quantity shipped, and the lot, batch or serial numbers
Shipment details and date
A statement that the items conform to all requirements of the order
The name, title and signature of an authorized person

The US Federal Acquisition Regulation gives a useful model. Its standard CoC clause has the contractor certify that the supplies conform in all respects to the contract requirements, including specifications, drawings, packaging, marking and part number, and are in the quantity shown.

When Is a CoC Used Instead of Inspection?

A CoC lets a buyer accept goods on the supplier's word rather than inspecting every shipment. US federal rules allow it in place of source inspection when that is in the buyer's interest and either a defect would cause only a small loss or the supplier's record makes acceptable product likely.

It never gives up the buyer's right to inspect. The same clause says the buyer can still reject defective supplies within a reasonable time after delivery, and the supplier must then replace, correct or repair them at its own expense.

CoC vs Other Quality Documents

Document	Who issues it	What it says	What it proves
Certificate of conformance (CoC)	The supplier shipping the parts	The batch meets the order, drawing and specs	A signed declaration, not measured data
Material certification	The material producer, passed down the supply chain	The material lot's grade and properties	What the parts were made from
Inspection report (e.g. CMM or first-article report)	The inspector or quality department	Measured values against the drawing	That specific dimensions were checked
Non-conformance report (NCR)	Whoever found the problem	An item does not meet a requirement, and what will be done	That a deviation was recorded and dispositioned

A CoC is only as strong as the records behind it. For critical features, ask for an inspection report alongside it.

How to Request a Useful CoC

Write the CoC requirement into the purchase order, not into an email after the parts ship.
Say what it must reference: drawing number and revision, material specification and any special process or grade requirement.
Ask for lot or batch traceability where parts go into regulated or safety-related products.
Pair it with material certifications and a dimensional report when the application justifies it.

At NICE Rapid, a certificate of conformance and full batch traceability records are available on request for LSR molding, including ISO 10993 and FDA certificates of conformance for medical- and food-grade silicone. For other processes, CMM reports, material certifications and inspection documentation can be requested with the order.

Frequently Asked Questions

What is a certificate of conformance?

It is a document, signed by the supplier, stating that a specific shipment of parts or material meets the purchase order, drawing and specification requirements. It identifies the part number, revision, quantity and lot, and is often required before goods can be accepted.

Is a certificate of conformity the same as a certificate of conformance?

In supplier quality, yes: the two names are used for the same kind of document, a supplier's signed declaration that goods conform to stated requirements. Check the customer's or regulator's wording, since some require a specific format or content.

Does a CoC certificate replace inspection?

No. A CoC can reduce the buyer's own inspection, but it is a declaration rather than measured data. Under US federal rules, a buyer can still inspect and reject defective supplies after delivery, and the supplier must replace, correct or repair them.

Related Services at NICE Rapid

LSR Molding — certificate of conformance and full batch traceability records on request, with clean-room packing for medical-grade batches.
High-Volume Manufacturing — ISO 9001:2015 production with full batch records and PPAP documentation available.
Request a Quote — list the quality documents you need, such as a CoC, material certificates or a CMM report, when you send your files.

Sources

48 CFR 52.246-15, Certificate of Conformance (FAR clause), via Cornell Law School Legal Information Institute — the certificate text: supplies "conform in all respects with the contract requirements, including specifications, drawings, preservation, packaging, packing, marking requirements, and physical item identification (part number)" and quantity; the Government keeps the right to reject defective supplies, which the contractor must replace, correct or repair at its expense — law.cornell.edu
48 CFR 46.504, Certificate of conformance (FAR), via Cornell LII — a CoC may be used instead of source inspection when it is in the Government's interest and small losses would result from a defect or the contractor's reputation or past performance makes acceptable supplies likely; the right to inspect is not prejudiced — law.cornell.edu