Example data table
| Class Code | Description | Payroll ($) | Rate / $100 | Manual Premium ($) |
|---|---|---|---|---|
| 8810 | Clerical office employees | 250,000 | 0.25 | 625.00 |
| 8742 | Outside salespersons | 180,000 | 0.35 | 630.00 |
| 5606 | Contractor - project manager | 120,000 | 3.10 | 3,720.00 |
Formula used
- Manual premium per class: Manual = (Payroll ÷ 100) × Rate
- Total manual: ManualTotal = Σ Manual
- Experience rating: AfterExp = ManualTotal × E-Mod
- Schedule modification: AfterSched = AfterExp × (1 + Schedule%/100)
- Premium discount: AfterDisc = AfterSched × (1 − Discount%/100)
- Expense constant added: Base = AfterDisc + Expense
- Surcharges: Fees = BaseOrPremium × (Assessment% + Terrorism% + Cat%)/100
- Total then limited: Total = clamp(Base + Fees, Min, Max)
How to use this calculator
- Enter payroll for each workers’ compensation class code.
- Enter the rate per $100 of payroll for each class.
- Set your experience modifier, schedule adjustment, and discount.
- Choose assessments and optional surcharges if they apply.
- Optionally set minimum or maximum premium limits.
- Click Calculate premium to view results and graphs.
- Use the top buttons to download CSV or PDF reports.
Quick state notes
Payroll exposure and rate sensitivity
Premium begins with payroll divided by 100, multiplied by the class rate. A $500,000 payroll at a $2.50 rate produces $12,500 manual premium. If payroll rises 8%, manual premium rises 8% when rates stay constant. Use multiple rows to isolate higher risk crews from low risk staff, then compare the manual bar chart for concentration.
Experience modifier as a portfolio multiplier
The experience modifier scales the manual total. An E-Mod of 1.15 increases a $40,000 manual premium to $46,000, adding $6,000 before any other adjustments. A reduction from 1.15 to 0.95 would lower the same manual by $8,000. Track loss runs, return to work timelines, and claim frequency, because small changes compound across every class.
Schedule credits, debits, and discount layers
Schedule modification is applied after the E-Mod and is expressed as a percent. A -7% schedule on $46,000 yields $42,780, while a +10% schedule yields $50,600. Premium discount then applies to the scheduled premium. A 12% discount on $42,780 reduces it to $37,646. This calculator separates each layer so the waterfall view shows exactly where changes occur.
Assessments and optional surcharges planning
Assessments, terrorism, and catastrophe charges are modeled as percentage surcharges. If assessments are 2.0% and the surcharge base is $37,646, the assessment adds $752.92. Adding a 0.5% catastrophe charge would add $188.23. If your program applies surcharges to premium only, keep “include expense in surcharges” set to No for closer alignment with common fee bases.
Minimum and maximum premium guardrails
Minimum premium provisions can override calculated totals on smaller policies. For example, a computed subtotal of $1,850 with a $2,500 minimum results in a $650 increase. Maximum limits may cap exposure during rapid growth, but may also indicate rating exceptions. Use the CSV export to document assumptions, then update class payroll monthly so budgeting reflects staffing changes and seasonality. When reviewing scenarios, test a 5% payroll swing and a 0.05 E‑Mod change to see which lever dominates, then set contingency reserves accordingly for next cycle.
FAQs
1) What does “rate per $100” mean?
It is the published class rate applied to each $100 of payroll. For example, a $2.50 rate on $100,000 payroll produces ($100,000 ÷ 100) × 2.50 = $2,500 manual premium.
2) Should I include overtime in payroll?
Use the payroll basis required by your jurisdiction and carrier. Many programs include overtime at straight-time wages only. If you are unsure, model both cases to understand the premium sensitivity.
3) Why does the E-Mod change everything?
The experience modifier multiplies the entire manual premium. A small shift, such as 1.05 to 1.10, affects every class row, so its impact is often larger than changing a single class rate.
4) What is the schedule modification?
Schedule mod is an underwriting credit or debit applied after the E-Mod. It reflects qualitative factors such as safety programs, controls, and management practices, and is usually expressed as a percentage.
5) Why are my totals different from a carrier quote?
Quotes can include state-specific rules, rounding, minimums, special funds, and fee bases that vary by program. Use this tool for planning and scenario analysis, then reconcile differences with the carrier worksheet.
6) What does the waterfall chart show?
It visualizes how the manual premium becomes the final estimate. Each step adds or subtracts the E-Mod impact, schedule impact, discount impact, fixed expense, and selected surcharges, ending at the total.