Rex says
Money math without the spreadsheet headache. Plug in your numbers and I'll show you exactly where the dollars land.
Try a scenario
Click to load — tweak from there.Inputs
Result
Estimated annual premium
$21,625
Manual premium (before mod)
$22,500
Premium after e-mod
$22,500
Dollar impact of e-mod
$0
Rough cost per employee
$1,946
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How to use this
- 1Enter annual payroll for this class code ($).
- 2Enter class code rate per $100 payroll ($).
- 3Enter experience modification factor.
- 4Enter schedule credit for safety programs (%).
- 5Enter expense constant / policy fee ($).
- 6Read your estimated annual premium on the right — it updates as you type.
- 7Hit Share to keep the scenario or send it to someone.
About this calculator
Workers' compensation premium is driven by three core inputs: payroll (in $100 units), the class code rate assigned by your state's rating bureau based on job hazard, and your experience modification factor (e-mod), which rewards or penalizes you relative to industry average loss history. The base formula is payroll divided by 100, multiplied by the class rate, multiplied by the e-mod. From there, insurers typically apply expense constants and any schedule credits or debits for safety programs. This calculator walks through that full chain so you can see exactly how a 0.85 e-mod (good loss history) versus a 1.20 e-mod (poor loss history) changes your bottom line, and how a schedule credit for safety training stacks on top of the mod adjustment.
Worked example
Using the values the calculator loads with:
Inputs
- Annual payroll for this class code: 500000 $
- Class code rate per $100 payroll: 4.5 $
- Experience modification factor: 1
- Schedule credit for safety programs: 5 %
- Expense constant / policy fee: 250 $
Results
- Estimated annual premium: $21,625
- Manual premium (before mod): $22,500
- Premium after e-mod: $22,500
- Dollar impact of e-mod: $0
- Rough cost per employee: $1,946
What each field means
Inputs
- Annual payroll for this class code ($)
- The annual payroll for this class code used in the calculation, measured in $. Starts at 500000 $ so you have a working example on load.
- Class code rate per $100 payroll ($)
- The class code rate per $100 payroll used in the calculation, measured in $. Starts at 4.5 $ so you have a working example on load.
- Experience modification factor
- The experience modification factor used in the calculation. Starts at 1 so you have a working example on load. Accepted range: 0.5–2.
- Schedule credit for safety programs (%)
- The schedule credit for safety programs used in the calculation, measured in %. Starts at 5 % so you have a working example on load. Accepted range: -25–25 %.
- Expense constant / policy fee ($)
- The expense constant / policy fee used in the calculation, measured in $. Starts at 250 $ so you have a working example on load.
Results
- Estimated annual premium
- Returned as a money amount in US dollars and shown as the headline result. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Manual premium (before mod)
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Premium after e-mod
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Dollar impact of e-mod
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Rough cost per employee
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
FAQ
What is an experience modification factor (e-mod)?
It's a multiplier calculated by your state's rating bureau (like NCCI) comparing your actual claims history to the expected losses for a business your size in your industry. A 1.00 mod means average; below 1.00 means better-than-average losses and lower premium; above 1.00 means worse losses and higher premium. It typically uses three years of loss history, excluding the most recent year.
Why does my payroll get divided by 100?
Workers' comp class rates are quoted per $100 of payroll by convention across the industry, dating back to how state rating bureaus originally published rate tables. A $4.50 rate means $4.50 of premium for every $100 an employee earns in that job classification, before any mod or credits.
How do I lower my workers' comp premium?
The two biggest levers are your e-mod (improve it by reducing claims frequency and severity over 3+ years) and correct class code assignment (misclassifying office staff under a higher-hazard code inflates cost). Schedule credits for documented safety programs, return-to-work programs, and drug testing can also shave 5–25% off premium in many states.
Can class codes vary for the same business?
Yes. A business often has multiple class codes — for example, a general contractor might have separate codes for office staff, carpenters, and roofers, each with a very different rate. Payroll must be tracked and reported separately by class code, and misallocating payroll to a lower-rated code is a common audit finding.
Accuracy and limitations
- Results are estimates before tax, fees, and inflation unless an input explicitly covers them.
- Rates are treated as fixed for the whole period — variable-rate products will drift from this projection.
- This is educational maths, not financial advice. Check anything contractual with the lender or your accountant.
Related tools
Cite this calculator
Writing about this topic? Grab a citation — every link helps keep these tools free.
RevenueLab. (2026). Workers' Comp Premium Calculator (Class Code & Mod). Retrieved from https://www.revenuelab.fyi/toolbox/workers-comp-premium-by-class-code
<p>Source: <a href="https://www.revenuelab.fyi/toolbox/workers-comp-premium-by-class-code" target="_blank" rel="noopener">Workers' Comp Premium Calculator (Class Code & Mod) — RevenueLab</a> (2026).</p>
Source: [Workers' Comp Premium Calculator (Class Code & Mod) — RevenueLab](https://www.revenuelab.fyi/toolbox/workers-comp-premium-by-class-code) (2026).