How is workers' comp premium calculated in Pennsylvania?

The standard formula is (annual payroll / 100) x class code base rate x experience modification factor. Payroll is divided by 100 because workers' comp rates are quoted per $100 of payroll. The experience mod adjusts the manual premium up or down based on your past claims history.

What is an experience modification factor?

The experience modifier (or 'mod') compares your business's actual loss history to expected losses for similar firms. A mod of 1.0 is average; below 1.0 (e.g., 0.85) earns a credit and lowers premium, while above 1.0 (e.g., 1.20) is a debit that raises it.

Where do class code rates come from in Pennsylvania?

Pennsylvania uses classification codes and base rates filed by the Pennsylvania Compensation Rating Bureau (PCRB), not the national NCCI. Each occupation has a rate per $100 of payroll reflecting its injury risk — clerical work is cheap, roofing and logging are expensive.

Is workers' comp required in Pennsylvania?

Yes. Pennsylvania requires nearly all employers to carry workers' compensation coverage for employees, either through a private carrier, the State Workers' Insurance Fund (SWIF), or approved self-insurance. Failure to carry it can bring fines and criminal penalties.

Does this estimate include all premium charges?

This is a manual-premium estimate. Final premium can include schedule credits or debits, expense constants, terrorism and catastrophe loadings, premium discounts for size, and assessments. Always get a quote from a licensed carrier for the binding figure.

Pennsylvania Workers' Compensation Premium Calculator

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The Pennsylvania workers’ compensation calculator estimates an employer’s annual premium using the manual-premium formula that PA carriers apply. It rests on three inputs: your annual payroll, the base rate for your job classification code, and your experience modification factor.

How it works

Workers’ comp rates are quoted per $100 of payroll, so the math is:

manual premium = (annual payroll / 100) x class base rate
final premium  = manual premium x experience modifier

The experience modifier (mod) reflects your claims history — below 1.0 is a credit, above 1.0 is a debit. A mod of 1.0 means no adjustment.

Worked example

$500,000 payroll, a class rate of $3.50 per $100, mod of 0.90:

Manual premium: (500,000 / 100) x 3.50 = $17,500
Final premium: 17,500 x 0.90 = $15,750

If that same business had a poor loss record and a 1.25 mod instead, the premium would rise to 17,500 x 1.25 = $21,875.

Tips and notes

Rates come from the PCRB. Pennsylvania uses the Pennsylvania Compensation Rating Bureau’s classification codes and base rates, not the national NCCI system used in most states.
High-risk codes cost far more. Roofing or logging rates can be many dollars per $100, while clerical codes are often under $0.50.
The mod is your biggest lever. Reducing claims and improving safety lowers your experience mod year over year, directly cutting premium.
This is an estimate. Final premium can add expense constants, schedule credits/debits, and assessments — get a carrier quote for the binding number.