Workers’ comp premium calculator
Workers’ compensation is priced per $100 of payroll for each job class, then adjusted for your claims history. Enter your payroll and your class rate to see each step of the calculation. In Ohio, Washington and Wyoming the state fund publishes every class rate, so entering a class code fills in the official rate.
Estimated annual premium
$186.40
| Manual premium | $400,000 ÷ 100 × 0.0466 = $186.40 |
|---|---|
| After experience mod | $186.40 × 1.00 = $186.40 |
| After credits and debits | $186.40 × (1 + 0%) = $186.40 |
| After surcharges | $186.40 × (1 + 0%) = $186.40 |
Example: an Ohio office with $400,000 of clerical payroll at the state fund’s published base rate. Ohio charges at least its $120 minimum administrative charge a year.
The formula insurers use
Every state follows the same basic sequence, although the names of the steps differ:
Rate × payroll
Each job class has a rate per $100 of payroll (per hour worked in Washington). Payroll for each class is divided by 100 and multiplied by its rate; the results are added together. This is the manual premium.
Experience modification
Businesses large enough to be experience rated have a modification factor that compares their own claims with those expected for their size and classes. A mod of 0.85 cuts the premium by 15%; 1.25 raises it by 25%. See how the experience mod works.
Credits, debits and discounts
Insurers in most states may apply schedule credits or debits within limits filed with the regulator, premium discounts on larger policies and programs such as drug-free workplace credits.
Assessments and fees
States add assessments that fund their workers’ compensation agencies and special funds, and insurers add expense constants and terrorism or catastrophe charges. Your state page lists what applies where we could confirm it.
Where the rate comes from
In Ohio, Washington and Wyoming the state fund is the only insurer, and it publishes each class’s rate: Ohio (501 classes, effective 1 Jul 2026), Washington (320 classes, effective 1 Jan 2026) and Wyoming (127 classes, effective 1 Jan 2026). Elsewhere, a rating bureau publishes loss costs and each insurer multiplies them by its own factor, so the rate on your quote or policy is the one to enter. Where each state’s rates are published.
What this estimate leaves out
- Minimum premiums and expense constants, which matter most for very small payrolls.
- Premium discounts for large policies, dividends and retrospective rating.
- Washington employers withhold part of the hourly rate from wages; the calculator shows the full rate.
- The final premium is set by the payroll audit after the policy year, not by the estimate at the start. See premium audits.