In workers’ compensation, the manual premium is the baseline cost of a policy before any credits, debits, or other adjustments. It comes from two inputs only: the classification code assigned to each type of work your employees perform, and the payroll paid under each code. Divide the payroll for a classification by 100, multiply by that classification’s rate, repeat for every code on the policy, and add the results. That total is your manual premium.
The Formula
Workers’ comp rates are quoted per $100 of payroll. For a single classification, the math is:
- Annual payroll ÷ 100 = payroll units
- Payroll units × rate = manual premium for that classification
If you have $500,000 in payroll under a classification rated at $2.50 per $100:
- $500,000 ÷ 100 = 5,000 payroll units
- 5,000 × $2.50 = $12,500
Most businesses carry employees in more than one classification. A contractor might have field crews under one code, office staff under another, and a salesperson under a third. Run the calculation separately for each code, then add. The sum is the manual premium for the policy.
At policy inception, the payroll figures are estimates for the coming year, so the number is sometimes called the estimated manual premium. Actual payroll gets reconciled after the policy expires, through the audit.
Classification Codes: The First Input
Every job function is assigned a four-digit classification code based on the injury risk it carries. The National Council on Compensation Insurance (NCCI) maintains these codes in its Scopes Manual, with detailed descriptions of the operations and exposures expected under each code in every state where NCCI operates.1National Council on Compensation Insurance. Scopes Manual A separate Classification Codes and Statistical Codes Manual cross-references the numbers.2NCCI. Classification Codes and Statistical Codes for Workers Compensation and Employers Liability Insurance
The codes reflect real differences in loss experience. A plumbing operation under code 5183 carries a far higher rate than a clerical office under code 8810, because plumbers get hurt more often and more severely than people at desks. If you already have a policy, your codes are listed on the declarations page. New businesses can look them up through NCCI’s online tools or ask their agent.
A few rules shape how codes get assigned. Every workplace has a governing classification, meaning the basic classification that generates the most payroll at that location. Certain occupations, including clerical workers, outside salespeople, and drivers, are treated as standard exceptions and get their own code regardless of the employer’s primary business. Employees who float between tasks can be assigned to the governing classification unless you keep payroll records showing exactly how their time breaks down. If your records don’t separate payroll by classification, the insurer will assign everything to the highest-rated code on the policy.
Payroll: The Second Input
Payroll in a manual premium calculation is not the same as total compensation. The NCCI Basic Manual defines precisely what goes in and what stays out, and the distinction can shift your premium meaningfully.3NCCI. Basic Manual for Workers Compensation and Employers Liability Insurance
Payroll that counts includes regular wages and salaries, retroactive pay adjustments, holiday, vacation and sick pay, commissions (including draws against commissions), and bonuses, including stock bonus plans.
Payroll that doesn’t count includes:
- Tips and gratuities, excluded entirely
- Overtime premium, meaning only the extra pay above the regular hourly rate (if someone earning $20 an hour works overtime at $30, only the extra $10 per overtime hour comes out)
- Severance and dismissal payments, unless they cover time actually worked or accrued vacation
- Employer contributions to group insurance, pension plans, retirement plans, and cafeteria plans under IRC Section 125
- Perks and non-cash compensation such as company vehicles, incentive vacations, club memberships, and event tickets
- Uniform allowances and supper money
- Business expense reimbursements, if the employer’s records confirm the expenses were legitimate business costs, shown separately for each employee
Your books have to support these exclusions. Overtime premium only comes out if your records show overtime pay separately by employee and summarized by classification. No records, no exclusion. The same principle applies to expense reimbursements and to subcontractor payments: if you can’t document them properly, they get added back into payroll at audit time.
Where the Rate Comes From
The “rate” in the formula deserves a closer look, because what it represents depends on your state. In most NCCI states, what NCCI actually publishes is not a final rate but a loss cost. The loss cost reflects only the expected cost of paying claims, meaning indemnity benefits, medical expenses, and loss adjustment expenses. It does not include the carrier’s overhead for commissions, administrative expenses, taxes, or profit.4NCCI. Ratemaking Resource Guide
Each carrier then files its own loss cost multiplier (LCM) with the state to convert NCCI’s loss cost into the rate it charges. The LCM accounts for the carrier’s own claims experience relative to the industry average and for its expense and profit needs.5National Association of Insurance Commissioners. Loss Cost Memorandum – All Lines of Property and Casualty Insurance A carrier with lower expenses and better claims results can file a lower LCM, which produces a lower rate. One with higher costs files a higher LCM.
If NCCI’s loss cost for a classification is $1.80 and a carrier’s LCM is 1.35, the rate that carrier charges is $2.43 per $100 of payroll. A competing carrier with an LCM of 1.50 would charge $2.70 for the same classification. This is why quotes from different carriers vary even when the underlying loss cost is identical.
NCCI serves as the rating bureau for most states and files revised loss costs annually, reflecting medical cost inflation, claim frequency trends, and legislative changes. Your manual premium can move from one term to the next even if your payroll and codes don’t change. Eleven states run their own independent rating bureaus: California, Delaware, Indiana, Massachusetts, Michigan, Minnesota, New Jersey, New York, North Carolina, Pennsylvania, and Wisconsin. Four states (North Dakota, Ohio, Washington, and Wyoming) operate monopolistic state funds, so employers there buy coverage directly from the state. The methodology is similar, but the specific rules follow the state’s own system rather than NCCI’s.
From Manual Premium to Final Bill
The manual premium is only the starting number. Several adjustments then stack on top of it before you see a final figure.
The experience modification factor, or E-mod, compares your actual claims history over roughly a three-year window to what NCCI expected for a business of your size and classification mix. A mod of 1.00 is average. Below 1.00 is a credit; above 1.00 is a surcharge. You have to meet a minimum premium threshold to qualify for experience rating; very small employers don’t.6NCCI. ABCs of Experience Rating
Schedule rating is a separate adjustment that gives the underwriter discretion to credit or debit the premium based on qualitative factors the E-mod doesn’t capture: safety program, management commitment to loss control, premises condition, cooperation with prior carriers. Maximum credits and debits vary by state, ranging from 25% to as much as 50%.
A premium discount applies to larger policies, on the logic that servicing a $500,000 policy doesn’t cost ten times what servicing a $50,000 policy costs. Rating bureaus publish discount tables that step up through brackets as the premium grows.
A few smaller charges round out the policy. An expense constant, usually in the $100 to $350 range, is a flat fee added to every policy to cover baseline administrative costs. NCCI also includes two small catastrophe provisions in its loss costs: a terrorism provision tied to the federal Terrorism Risk Insurance Act, typically about a half-cent per $100 of payroll, and a general catastrophe provision for pandemics, earthquakes, and similar events, roughly a penny.7NCCI. Workers Compensation Catastrophes – Past, Present, and Future A minimum premium applies if the calculated figure comes in below the floor set for your governing classification.
The full sequence runs from the manual premium through the E-mod, then schedule rating, then the premium discount, then the expense constant, catastrophe provisions, and any state surcharges.
The Audit Reconciles the Estimate
Because the manual premium at policy inception uses projected payroll, every workers’ comp policy requires a premium audit after the policy period ends. An auditor reviews actual payroll, verifies classification assignments, and recalculates the premium. If actual payroll came in higher than projected, you owe additional premium. If it came in lower, you get a refund. The audit also catches classification errors and triggers a recalculation at the correct rates.
Records that should be ready for the auditor include quarterly tax filings (Form 941), W-2s, and detailed payroll journals showing pay by employee and classification; owner and officer information with titles, ownership percentages, and earnings; 1099s and certificates of insurance for every subcontractor; and the general ledger, cash receipts journal, and sales tax records.
Where employers lose money on manual premium is almost always in the inputs they control: inaccurate payroll estimates that trigger big audit bills, poor recordkeeping that blocks overtime or subcontractor exclusions, misclassified employees who inflate the rate, and safety programs the carrier never heard about and so never credited. The formula is mechanical. The savings come from feeding it clean data.