Your experience modification rate (EMR or "ex-mod") is the multiplier that raises or lowers your workers’ comp premium based on your claims history versus businesses like yours. An EMR of 1.00 is average; below 1.00 is a discount, above 1.00 is a surcharge. This experience mod calculator estimates your mod from actual vs. expected losses and shows the dollar impact on your premium. Enter your figures below to see your EMR and what it costs or saves you.
The EMR compares your actual losses to the expected losses for a business of your size and class. In simplified terms:
EMR ≈ actual losses ÷ expected losses
| EMR | Meaning | Premium effect |
|---|---|---|
| Below 1.00 (e.g., 0.85) | Better than average safety | 15% discount |
| 1.00 | Average for your class | No change |
| Above 1.00 (e.g., 1.25) | Worse than average | 25% surcharge |
Because the mod multiplies the entire premium, a small change has a big dollar effect. Dropping from 1.25 to 1.00 on a $60,000 manual premium saves $15,000 a year — every year it holds.
A firm has $40,000 in actual losses over the rating period against $50,000 of expected losses, with a $60,000 manual premium:
If instead actual losses were $75,000 (mod 1.50), the premium would jump to $90,000 — a $30,000 surcharge. Same business, same payroll: the only difference is claims history.
The official NCCI/bureau calculation is more nuanced than actual ÷ expected. It:
This is why two firms with identical total losses can have different mods — many small claims signal ongoing risk more than a single big one. Treat the calculator’s number as a directional estimate, not the filed mod.
Because premium = (payroll ÷ 100) × rate × EMR, the mod sits on top of everything. A lower EMR amplifies every other saving you make — correct class codes, excluded overtime premium, schedule credits. Many general contractors and government bids also require an EMR at or below 1.00 to qualify, so the mod affects not just cost but eligibility for work. Pair this with our premium-by-class-code calculator to see the full picture.
In simplified terms, EMR equals your actual losses divided by the expected losses for a business of your size and class. The official NCCI or state-bureau formula is more detailed — it splits losses into primary and excess portions, adds ballast and weighting values, and uses three of the last four policy years.
An EMR of 1.00 is the industry average. Below 1.00 means better-than-average loss experience and a premium discount; above 1.00 means a surcharge. Many contractors target 0.90 or lower, and some general contractors and public bids require an EMR at or below 1.00 to qualify for work.
The EMR multiplies your entire manual premium. At a $60,000 manual premium, a 0.80 mod cuts the cost to $48,000 (a $12,000 saving), while a 1.25 mod raises it to $75,000. Because it scales the whole premium, even small mod changes move thousands of dollars.
The rating formula weights the 'primary' (capped) portion of each claim heavily and discounts the 'excess' portion. Many small claims each contribute a full primary amount, signaling ongoing risk, while a single large claim's excess is discounted. So claim frequency raises the mod more than one severe claim of the same total dollars.
Reduce claim frequency, return injured workers to light duty quickly, report and manage claims early, audit open reserves on stale claims before the rating snapshot, and verify the payroll and claim data on your bureau worksheet for errors. Improvements show up in future policy years, not immediately.