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Workers’ Compensation Premium & Audit Calculator

Updated Oct 2026
Method, evidence and jurisdiction contextChoose the rate convention and confirm whether this simple payroll-rated sequence matches the written policy or scheme.
Changes currency and jurisdiction context only. The calculator never supplies a class code, rate, legal requirement, exemption, payroll cap, scheme rule, or exchange rate.
Both formats use payroll × rate ÷ 100. Copy the exact convention from the policy, bureau, board, authority, or quote.
An audit estimate is strongest when class payroll and rates come from the declarations, audit worksheet, authority statement, and payroll ledger.
The tool does not decide which classification, jurisdiction, occupation, payroll item, contractor, officer, partner, or cap applies.
Use the numerical reconciliation only for a payroll-rated method that can be represented by the entered sequence.
Prevents double counting. Some boards and schemes provide a net rate that already reflects experience; many private-market policies show a manual rate before modifiers.
Policy-level modifiers and chargesCopy only documented factors. Net rates that already include experience adjustments must not be adjusted twice.
Enter the issued factor only when the class rates are pre-adjustment. Use 1.00 when no factor applies.
Enter a negative percentage for a credit and a positive percentage for a debit. The model applies it after the experience modifier.
Entered percentage reduction applied after experience and schedule adjustments. Use only if documented.
Minimum charge for the entered policy or scheme. Confirm whether it already includes the expense constant.
The sequence changes the result when calculated premium is below the minimum.
Flat charge kept outside experience and premium-discount calculations.
Optional charge per selected payroll basis, applied to total payroll after the minimum-premium step. Enter 0 when not applicable.
Applied to premium after the minimum/expense and payroll-based charge, before fixed fees. Verify the actual assessment base.
Total fixed charges not already entered as the expense constant or percentage assessment.
Amount already paid for the same policy or reporting period. The final balance compares this amount with the modeled audited total.
Classification 1Enter the original payroll/rate and the audited payroll/rate for the same row. Leave all four values at zero when unused.
Insurable or rateable payroll originally assigned to this written classification or industry group.
Original rate copied from the policy, quote, board, scheme, or authority statement. Use 0 only when both estimated and audited payroll for this row are 0.
Actual insurable or rateable payroll assigned to this row after the period.
Rate the audit or reconciliation applies to actual payroll. A difference from the original rate isolates classification or rate impact.
Classification 2Enter the original payroll/rate and the audited payroll/rate for the same row. Leave all four values at zero when unused.
Insurable or rateable payroll originally assigned to this written classification or industry group.
Original rate copied from the policy, quote, board, scheme, or authority statement. Use 0 only when both estimated and audited payroll for this row are 0.
Actual insurable or rateable payroll assigned to this row after the period.
Rate the audit or reconciliation applies to actual payroll. A difference from the original rate isolates classification or rate impact.
Classification 3Enter the original payroll/rate and the audited payroll/rate for the same row. Leave all four values at zero when unused.
Insurable or rateable payroll originally assigned to this written classification or industry group.
Original rate copied from the policy, quote, board, scheme, or authority statement. Use 0 only when both estimated and audited payroll for this row are 0.
Actual insurable or rateable payroll assigned to this row after the period.
Rate the audit or reconciliation applies to actual payroll. A difference from the original rate isolates classification or rate impact.
Classification 4Enter the original payroll/rate and the audited payroll/rate for the same row. Leave all four values at zero when unused.
Insurable or rateable payroll originally assigned to this written classification or industry group.
Original rate copied from the policy, quote, board, scheme, or authority statement. Use 0 only when both estimated and audited payroll for this row are 0.
Actual insurable or rateable payroll assigned to this row after the period.
Rate the audit or reconciliation applies to actual payroll. A difference from the original rate isolates classification or rate impact.

Guest calculations stay on this device. Signed-in results sync privately.

Your result

Audited total premium

Enter your values, then calculate to see a verified result.

Inputs usedReview the information used for this result.
Full calculation and sourcesOpen the result to audit every class row and each premium step from payroll × written rate through modifiers, minimum premium, charges, assessments, paid-to-date balance, and the audit true-up.

Versioned calculationFormula v1.0.0

One user-entered policy, board, scheme, or reconciliation periodUser-entered written class rates, estimated payroll, audited payroll, modifiers, charges, fees, and amount paidFormula v1.0.0

What is calculated

Method

The entered values are normalized, validated, and passed to the versioned calculation.

Important boundary

This result is an estimate. Confirm important decisions against the relevant source or professional guidance.

Result actions
1
Enter the inputsAdd the values and choose the options required for this calculation.Required fields
2
Run the calculationValidate the inputs and apply the versioned method.Formula v1.0.0
3
Review the resultRead the answer together with its context and important boundary.Result + assumptions

Interpretation

The result reflects the current inputs and selected workflow.

Calculated with the versioned 1.0.0 model.

Review the result assumptions and important boundary before acting on the plan.

Use this result

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4 related pages
Method and test recordFormula v1.0.0
Recorded scope
Not recorded
Publisher
CalculatorGeek
Recorded review date
Not recorded
Next source review
Not scheduled
Definition fixtures
3 configured scenarios
Published examples
3 shown below

Recorded method

No tool-specific review method has been recorded.

These records describe the published model and reference tests. A test-case count is not a certification of every possible input or an independent specialist review. Editorial policy

Known limitations

    Method sources

    Reference inputs and expected results

    Up to 12 examples from the configured definition fixtures are shown. Expected values use the stated output units; invalid inputs are intended to be rejected.

    CaseInputsExpected result
    default multi-class premium auditMarket and currency: us; How the entered rate is written: per_100; Payroll evidence: policy_and_payroll_records; Classification and rate status: confirmed_written_rates; Premium method scope: simple_payroll_rated; Stage of the entered class rates: before_experience_adjustments; Experience modifier or claims factor: 0.92 count; Schedule credit (−) or debit (+): -5 pct; Premium discount: 3 pct; Minimum premium: 1000 currency; Minimum premium and expense constant: minimum_includes_expense; Expense constant or fixed policy charge: 250 currency; Payroll-based terrorism or other charge rate: 0.02 rate; Assessment, levy, or percentage surcharge: 2 pct; Other fixed fees or installment charges: 150 currency; Premium paid or deposited for the period: 20000 currency; Class 1 estimated payroll: 200000 currency; Class 1 original rate: 0.35 rate; Class 1 audited or actual payroll: 220000 currency; Class 1 audited rate: 0.35 rate; Class 2 estimated payroll: 350000 currency; Class 2 original rate: 5.2 rate; Class 2 audited or actual payroll: 420000 currency; Class 2 audited rate: 5.8 rate; Class 3 estimated payroll: 100000 currency; Class 3 original rate: 0.8 rate; Class 3 audited or actual payroll: 90000 currency; Class 3 audited rate: 0.8 rate; Class 4 estimated payroll: 0 currency; Class 4 original rate: 0 rate; Class 4 audited or actual payroll: 0 currency; Class 4 audited rate: 0 rateEstimated total payroll: 650000; Audited total payroll: 730000; Estimated manual premium: 19700; Audited payroll at original rates: 23330; Audited manual premium: 25850 (allowed numeric tolerance: 0.011)
    net board rates bypass experience and schedule adjustmentsMarket and currency: us; How the entered rate is written: per_100; Payroll evidence: policy_and_payroll_records; Classification and rate status: confirmed_written_rates; Premium method scope: simple_payroll_rated; Stage of the entered class rates: net_rates_include_adjustments; Experience modifier or claims factor: 1.25 count; Schedule credit (−) or debit (+): 10 pct; Premium discount: 0 pct; Minimum premium: 0 currency; Minimum premium and expense constant: minimum_includes_expense; Expense constant or fixed policy charge: 0 currency; Payroll-based terrorism or other charge rate: 0 rate; Assessment, levy, or percentage surcharge: 0 pct; Other fixed fees or installment charges: 0 currency; Premium paid or deposited for the period: 2000 currency; Class 1 estimated payroll: 100000 currency; Class 1 original rate: 2 rate; Class 1 audited or actual payroll: 120000 currency; Class 1 audited rate: 2 rate; Class 2 estimated payroll: 0 currency; Class 2 original rate: 0 rate; Class 2 audited or actual payroll: 0 currency; Class 2 audited rate: 0 rate; Class 3 estimated payroll: 0 currency; Class 3 original rate: 0 rate; Class 3 audited or actual payroll: 0 currency; Class 3 audited rate: 0 rate; Class 4 estimated payroll: 0 currency; Class 4 original rate: 0 rate; Class 4 audited or actual payroll: 0 currency; Class 4 audited rate: 0 rateEstimated premium after experience: 2000; Estimated schedule adjustment: 0; Audited total premium: 2400; Modeled balance after paid premium: 400 (allowed numeric tolerance: 0.011)
    minimum includes expense constantMarket and currency: us; How the entered rate is written: per_100; Payroll evidence: policy_and_payroll_records; Classification and rate status: confirmed_written_rates; Premium method scope: simple_payroll_rated; Stage of the entered class rates: before_experience_adjustments; Experience modifier or claims factor: 1 count; Schedule credit (−) or debit (+): 0 pct; Premium discount: 0 pct; Minimum premium: 500 currency; Minimum premium and expense constant: minimum_includes_expense; Expense constant or fixed policy charge: 200 currency; Payroll-based terrorism or other charge rate: 0 rate; Assessment, levy, or percentage surcharge: 0 pct; Other fixed fees or installment charges: 0 currency; Premium paid or deposited for the period: 500 currency; Class 1 estimated payroll: 10000 currency; Class 1 original rate: 1 rate; Class 1 audited or actual payroll: 10000 currency; Class 1 audited rate: 1 rate; Class 2 estimated payroll: 0 currency; Class 2 original rate: 0 rate; Class 2 audited or actual payroll: 0 currency; Class 2 audited rate: 0 rate; Class 3 estimated payroll: 0 currency; Class 3 original rate: 0 rate; Class 3 audited or actual payroll: 0 currency; Class 3 audited rate: 0 rate; Class 4 estimated payroll: 0 currency; Class 4 original rate: 0 rate; Class 4 audited or actual payroll: 0 currency; Class 4 audited rate: 0 rateEstimated standard premium: 100; Estimated minimum-premium top-up: 200; Estimated amount after minimum and expense: 500; Estimated total premium: 500 (allowed numeric tolerance: 0.011)

    Report an issue with this tool. Include the page URL, units, expected answer, and steps to reproduce. Do not include sensitive personal information.

    On this page

    What the result means

    The modeled audit adjustment equals audited total premium minus estimated total premium. A positive amount means the entered audited exposure produces more premium; a negative amount indicates a potential return premium or credit. The balance after paid premium separately compares the audited total with what has actually been paid.

    The calculator contains no live rates and does not supply or assign a class code. Enter those values only from the applicable written source.

    After calculating, use the payroll audit checklist to reconcile the result to written records.

    Core premium formula

    For each class row, manual premium is payroll × entered rate ÷ 100. The Texas Department of Insurance uses this rate-per-100 structure, and Ontario WSIB states the same calculation for insurable earnings. Australian schemes commonly express industry rates as a percentage of wages, which is arithmetically equivalent when the rate is entered as a number such as 2.50.

    Continue with Reconcile the audit worksheet or Investigate a class-rate change for the next calculation.

    Calculation order used here

    1. Calculate manual premium for each class.
    2. If the entered rates are pre-adjustment, apply the experience factor and schedule credit/debit.
    3. Subtract the entered premium discount.
    4. Apply the selected minimum-premium and expense-constant treatment.
    5. Add the payroll-based charge.
    6. Apply the assessment percentage to that subtotal.
    7. Add other fixed fees.
    8. Compare original and audited totals, then compare the audited total with premium paid.

    A policy or scheme can use a different base or sequence. Match this ledger to the written calculation before relying on it.

    Payroll change versus rate or classification change

    The tool first applies actual payroll to the original rate. That intermediate total isolates what changed because payroll moved. It then applies the audited rate, isolating the remaining effect from a changed rate or classification. This bridge is especially useful when a single audit bill combines workforce growth with a reclassification.

    Avoid double-counting an experience adjustment

    A US private-market manual rate may be adjusted later by an experience modifier. A Canadian compensation board or Australian scheme may instead present a net premium rate that already includes claims experience. Select net rates already include experience adjustments to bypass the experience and schedule steps in this model.

    Minimum premium and expense constant

    Minimum-premium wording matters. Under the selected “minimum includes expense” treatment, the model compares the minimum with standard premium plus the expense constant. Under the alternate treatment, it applies the minimum to standard premium and then adds the expense constant. Confirm the exact policy or scheme rule.

    Worked multi-class audit example

    The default scenario starts with 650,000 of estimated payroll and 19,700 of manual premium. Audited payroll rises to 730,000. Applying the original rates to actual payroll produces 23,330, so 3,630 of the manual-premium change is attributable to payroll. Audited rates produce 25,850, adding a further 2,520 rate/classification effect before later adjustments.

    Records to collect before an audit

    • Policy declarations, class or industry codes, original rates and endorsements.
    • Payroll journals by employee, duty, location and reporting period.
    • Overtime detail, bonuses, commissions and included benefits.
    • Officer, partner and owner records plus applicable minimums, maximums or exemptions.
    • Contractor certificates, contracts, invoices and separated labor/material records.
    • Experience-rating worksheet, schedule credits/debits, premium discount and assessments.
    • Audit worksheet, endorsements, invoices and paid-premium ledger.

    United States boundary

    Workers’ compensation is state-specific. Classification systems, loss costs or rates, monopolistic funds, experience-rating eligibility, payroll rules, minimum premiums, terrorism charges, assessments and audit rights vary. Use the rate and treatment shown on the applicable policy or rating source; do not substitute a national average.

    Canada boundary

    Canadian workers’ compensation is administered by provincial and territorial boards. Ontario WSIB calculates premium from insurable earnings and a premium rate, while boards can apply their own earnings maximums, classifications and experience programs. Use the board’s written net rate and choose the net-rate path when its experience adjustment is already embedded.

    Australia boundary

    Australian workers’ compensation arrangements differ across states and territories. Industry classification, wages or remuneration, claims performance, levies, incentives, caps and declarations can affect the final amount. Enter the scheme’s written rate and charges; do not treat this generic worksheet as the statutory calculation.

    United Kingdom boundary

    The UK generally uses employers’ liability insurance rather than the North American workers’ compensation structure. HSE explains that most employers must carry employers’ liability cover, but an insurer’s premium method is not a universal statutory payroll formula. UK mode is therefore a reconciliation worksheet only when a written quote or policy actually supplies compatible payroll rates.

    How to investigate a large audit change

    Start with the class rows that contribute the largest audited manual-premium share. Reconcile payroll records, confirm why any rate changed, check whether contractors or officers were added, verify the experience and schedule factors, and trace the minimum premium, charges and assessments. A disagreement about classification or coverage needs the insurer, board, rating bureau, broker or qualified adviser—not an online formula.

    Important limitations

    This model excludes retrospective rating, assigned-risk adjustments, deductible credits, dividends, loss-sensitive plans, group rating, per-capita or hourly exposure, multi-state allocation, premium caps, employer-grouping rules, claims-performance formulas, cancellations, short-rate factors, refunds already processed, penalties, interest, taxes not entered and jurisdiction-specific rounding. It does not determine worker status, contractor exposure, coverage, compliance, classification or audit appeal rights.

    Frequently asked questions

    Is the audit adjustment the same as the amount currently due?

    Not always. The audit adjustment compares modeled audited and estimated totals. The balance after paid premium compares the audited total with the amount entered as paid and can differ because of installments, endorsements, credits or timing.

    Should I use a national average class rate?

    No. Use the rate from the applicable written policy, authority, compensation board or scheme. Averages can conceal major differences by jurisdiction, class, insurer and year.

    What if the auditor changed a class code?

    Enter the original rate and the audited rate on the same row to isolate the rate or classification effect. Then obtain the written reason and use the applicable review process if necessary.

    Does a lower actual payroll guarantee a refund?

    No. A higher audited rate, minimum premium, added exposure, fees, assessments or other policy rules can offset a payroll reduction.

    Can this calculate my experience modifier?

    No. Enter an issued factor only. Experience-rating formulas use jurisdiction-specific payroll, expected loss, actual loss and eligibility data.

    Sources and review status

    Sources and model boundaries were checked on 2026-10-08. CalculatorGeek Editorial Team reviewed and approved the full finance and insurance package on 2026-10-08. The cited organizations supplied source material; they did not review or endorse this CalculatorGeek package. Product terms, policy forms, laws, regulatory guidance and rates can change; current written documents and applicable authorities control.

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