What Is a Certificate of Insurance (COI)? A Plain-English Guide

A certificate of insurance (COI) is a one-page document — almost always an ACORD 25 form — that proves a business carries insurance. It names the insurance carrier, the policy numbers, the coverage limits, and the policy dates. If you hire subcontractors or vendors, you collect COIs so that when something goes wrong on your job or property, the claim lands on their insurance instead of yours.

That's the whole idea. The rest of this guide covers what's actually on the form, why people collect them, and where the process quietly breaks.

Who needs to collect certificates of insurance?

Anyone who lets another business work on their site, project, or property:

• General contractors collect COIs from every subcontractor before the sub sets foot on a job site.
• Property managers and HOAs collect them from landscapers, roofers, plumbers, cleaners — any vendor working on the property.
• Businesses of every kind collect them from the contractors who service their buildings and equipment.

If a sub's employee is injured on your site and the sub's workers' comp lapsed, the claim can climb up to your policy — and your premiums. The COI is your evidence that you checked.

What information is on a COI?

A standard ACORD 25 certificate shows:

Section	What it tells you
Producer	The insurance agency that issued the certificate
Insured	The business that holds the policies — this must match the vendor you hired
Insurers	The actual carriers (with NAIC numbers) backing each policy
Coverage lines	General liability, auto, umbrella, and workers' comp — each with policy numbers, effective and expiration dates, and dollar limits
Description of operations	Free-text section where endorsements like additional insured status are often noted
Certificate holder	You — the party the certificate was issued to

For a field-by-field walkthrough, see how to read an ACORD 25 form.

Is a COI the same as the insurance policy?

No — and this matters. A COI is issued as a summary for information only. It confers no coverage by itself, and the fine print says exactly that. Two practical consequences:

1. The certificate can be outdated the day after it's issued. If the vendor cancels the policy, your paper copy doesn't change.
2. Endorsements need checking. Being named an "additional insured" only works if a real endorsement (like form CG 20 10) is attached to the policy — a checked box on the certificate is a claim, not proof.

What should I check on a COI?

At minimum, five things:

1. The insured's name matches your vendor — exactly, not a sister LLC.
2. Coverage limits meet your requirements — e.g., $1M per occurrence / $2M aggregate general liability is the common floor for subcontractor requirements.
3. Policy dates are current — and won't expire mid-project.
4. Required endorsements appear — additional insured, waiver of subrogation, primary & non-contributory wording.
5. Workers' comp is present — the line vendors most often quietly drop.

How do people track COIs — and where it breaks

Most small contractors and property managers track certificates in a spreadsheet and chase renewals by email. It works at five vendors. By thirty, office managers report spending 8+ hours a week requesting, re-requesting, and hand-checking certificates — and an expired cert still slips through every renewal season. We wrote up the honest version of that approach (template included) in our COI tracking spreadsheet guide.

How do I verify a COI quickly?

You can check one certificate right now: upload the PDF — or the photo your sub texted you — to the free CertifiKit COI checker. It reads every field, compares the certificate against your requirements, and gives you a plain-English verdict in about 60 seconds, with the evidence shown for every result.