How to Fill Out a Workers’ Comp Audit Form (Voluntary / Mail Audit)
6 min read · Updated June 20, 2026
Smaller policies often get a voluntary (mail) audit — a packet you fill out yourself instead of an auditor visiting. That’s good news: you control the numbers. But fill it out carelessly and you’ll overpay. Here’s how to do it right.
What a voluntary audit is
Instead of an in-person review, the carrier sends a form asking for your payroll, subcontractor, and owner details for the policy period, with supporting documents attached. You report; they reconcile. How the audit works →
Gather before you start
- Payroll summary, plus 941s, W-2/W-3, and state filings to match it.
- Certificates of insurance and 1099s for every subcontractor.
- Owner/officer pay figures and your state’s cap.
Fill it out section by section
- Payroll by class — report wages under the correct class code, not all lumped into the governing class.
- Overtime — list it separately so the excess can be excluded (in most states). What counts as payroll →
- Owner/officer pay — apply the state cap rather than entering the full salary.
- Subcontractors — list each, and attach their COI. A sub with a valid WC certificate shouldn’t be added to your payroll; one without will be.
Double-check the overpay traps
Before you send it, confirm you separated overtime, capped owner pay, used the right classes, and attached every sub’s certificate. These four are where self-audits leak money. Full prep checklist →
If the result still looks wrong
Even after a careful form, request the worksheet and dispute errors in writing. The free audit dispute letter generator builds the letter for you. And run your subs through the COI Gap Checker before you report them.
General information for contractors, not legal or insurance advice. Audit forms and exclusions vary by state and carrier — confirm yours.
Frequently asked questions
What is a voluntary or mail workers’ comp audit?
A self-reported audit where you complete a form or packet with your payroll and subcontractor details and attach supporting documents, instead of an auditor visiting in person.
What do I need to fill out a workers’ comp audit form?
Payroll broken out by class and separating overtime, your 941s/W-2s/state filings, owner-officer pay, and certificates of insurance plus 1099s for every subcontractor.
What mistakes cause overpaying on a self-audit?
Not separating overtime excess, not applying the owner-officer cap, putting payroll in too high a class, and listing subcontractor payments without attaching their COIs.
See your own exposure — free
Two free tools, no signup: estimate your audit surprise, and check whether your subs’ COIs actually protect you.
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