Gera Tools

Oregon Workers' Compensation Premium Calculator

Estimate annual workers' comp insurance cost for your Oregon employees.

Estimates employer workers' compensation premium for Oregon using the classification code base rate per 100 dollars of payroll, the experience modification factor, and Oregon's per-hour Workers' Benefit Fund assessment unique to the state.

How is workers' comp premium calculated?

The core formula is payroll divided by 100, multiplied by the classification base rate, multiplied by your experience modification factor. The base rate reflects the injury risk of the job class, and the mod adjusts for your own claims history.

Workers’ compensation is a mandatory cost for nearly every Oregon employer, and it can be a meaningful line item. The premium depends on three things: how much you pay your workers, how risky their jobs are (the classification base rate), and your own claims history (the experience modification factor). Oregon adds one more piece most states don’t have — the Workers’ Benefit Fund assessment, charged per hour worked. This calculator combines all of them.

How it works

The standard workers’ comp premium formula, plus Oregon’s WBF assessment:

  1. Base premium. (Annual payroll / 100) × base rate. The base rate is dollars of premium per $100 of payroll for your classification code — a low-risk clerical class might be $0.30, a roofing class several dollars.
  2. Experience mod. Multiply by your experience modification factor (e-mod). Below 1.0 lowers premium for a good safety record; above 1.0 raises it.
  3. Workers’ Benefit Fund. Oregon charges a per-hour assessment (a few cents per hour). The calculator multiplies your total hours worked by the WBF cents-per-hour rate.

The result is your estimated annual cost: insurance premium plus the WBF assessment.

Tips and example

A landscaping firm with $400,000 payroll, a base rate of $4.50 per $100, and an e-mod of 1.0 has a base premium of (400,000 / 100) × 4.50 = $18,000. With a clean safety record dropping the mod to 0.85, premium falls to $15,300. Add the WBF: if employees worked 20,000 hours at, say, 2.2 cents per hour, that’s another $440.

To lower your premium, focus on the e-mod — safety programs and claims management compound year over year. This is a planning estimate; your binding premium reflects carrier loss costs, schedule credits/debits, minimum premiums and final-audit payroll, so confirm with your agent.