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Combined Ratio Calculator

Calculate insurance underwriting profitability by combining loss and expense ratios relative to earned premium.

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Combined Ratio—

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What Is the Combined Ratio?

The combined ratio is the definitive measure of underwriting profitability for property and casualty (P&C) insurance companies. It expresses the total cost of claims and operating expenses as a percentage of earned premium. According to Investopedia, a combined ratio below 100% signals that an insurer is paying out less in losses and expenses than it collects in premiums — the definition of underwriting profit.

The Combined Ratio Formula

The combined ratio is the sum of two component ratios:

  • Loss Ratio = Incurred Losses ÷ Earned Premium × 100
  • Expense Ratio = Underwriting Expenses ÷ Earned Premium × 100 (Financial Basis) or Underwriting Expenses ÷ Net Written Premium × 100 (Trade Basis)

Combined together: Combined Ratio = Loss Ratio + Expense Ratio

Equivalently expressed as a single formula: Combined Ratio = (Incurred Losses + Underwriting Expenses) ÷ Earned Premium × 100

Variables Defined

  • Incurred Losses: Total claims paid to policyholders plus the net change in loss reserves for the accounting period. This figure captures both settled claims and actuarial estimates of future claim obligations on in-force policies.
  • Underwriting Expenses: All costs directly associated with writing and servicing insurance policies — including agent and broker commissions (typically 10–20% of premium), state premium taxes, salaries of underwriting staff, and general administrative overhead.
  • Earned Premium: The share of written premiums that corresponds to coverage already provided. For a $12,000 annual policy incepting July 1, only $6,000 is earned by December 31, with the remaining $6,000 treated as unearned premium reserve.
  • Net Written Premium (Trade Basis): Total premiums written during the period after deducting reinsurance ceded. Used as the denominator for the expense ratio under the trade basis method.

Financial Basis vs. Trade Basis

The National Association of Insurance Commissioners (NAIC) recognizes two industry-standard approaches for computing the expense ratio component:

  • Financial Basis (Statutory/GAAP): Both the loss ratio and expense ratio use earned premium as the denominator. This produces the most time-consistent measure of profitability and aligns with statutory financial statement reporting. It is the standard for regulatory filings and annual reports.
  • Trade Basis: The loss ratio still divides by earned premium, but the expense ratio substitutes net written premium as the denominator. Because net written premium leads earned premium by several months during growth periods, the trade basis typically produces a modestly lower expense ratio. This method is frequently used in internal management reporting and peer benchmarking within the industry.

How to Interpret the Combined Ratio

  • Below 100%: Underwriting profit. The insurer retains more premium than it pays in losses and expenses. A ratio of 95% implies $0.95 of outflow for every $1.00 of earned premium — a $0.05 underwriting margin.
  • Exactly 100%: Break-even underwriting. Claims and expenses precisely consume all earned premium, leaving no underwriting margin.
  • Above 100%: Underwriting loss. The insurer pays out more than it collects. Insurers can still achieve overall profitability when investment income from the premium float offsets underwriting losses, but sustained ratios above 100% erode capital over time.

Step-by-Step Calculation Example

Consider a mid-size homeowners insurer with the following fiscal year 2024 figures:

  • Incurred Losses: $62,000,000
  • Underwriting Expenses: $18,000,000
  • Earned Premium: $100,000,000
  • Net Written Premium: $105,000,000

Financial Basis Calculation:

  • Loss Ratio = $62M ÷ $100M × 100 = 62.0%
  • Expense Ratio = $18M ÷ $100M × 100 = 18.0%
  • Combined Ratio = 62.0% + 18.0% = 80.0% — strong underwriting profit.

Trade Basis Calculation:

  • Loss Ratio = 62.0% (unchanged)
  • Expense Ratio = $18M ÷ $105M × 100 = 17.1%
  • Combined Ratio = 62.0% + 17.1% = 79.1%

Industry Benchmarks

NAIC data shows the U.S. property-casualty industry combined ratio has historically averaged between 98% and 102% across a full underwriting cycle. Catastrophe-heavy years — such as 2017 and 2022 — pushed industry-wide ratios above 107%. A combined ratio consistently below 95% is considered excellent underwriting performance, while figures above 110% trigger enhanced regulatory scrutiny of capital adequacy.

Sources

Reference

Frequently asked questions

What is a good combined ratio for an insurance company?
A combined ratio below 100% indicates underwriting profitability, meaning the insurer pays out less in claims and expenses than it collects in earned premium. Ratios below 95% are considered excellent in the P&C industry. The U.S. industry average historically runs between 98% and 102% over a full underwriting cycle, with major catastrophe years such as 2017 and 2022 pushing ratios above 107%.
What is the difference between financial basis and trade basis combined ratio?
The financial basis uses earned premium as the denominator for both the loss ratio and the expense ratio, providing the most period-consistent profitability measure and aligning with NAIC statutory reporting standards. The trade basis uses net written premium as the expense ratio denominator only. Because written premium leads earned premium during growth periods, the trade basis typically produces a modestly lower expense ratio and is common in management reporting and competitive benchmarking.
How is the combined ratio different from the loss ratio?
The loss ratio measures only incurred claims relative to earned premium (Incurred Losses divided by Earned Premium, times 100). The combined ratio adds the expense ratio — covering agent commissions, premium taxes, and administrative overhead — to the loss ratio. A carrier could post a favorable 60% loss ratio yet still show a combined ratio above 100% if underwriting expenses consume an additional 45% of earned premium.
Can an insurance company be profitable with a combined ratio above 100%?
Yes. Insurers invest the float — premiums collected before claims are paid — and can generate substantial investment income. If investment returns are large enough, they can offset an underwriting loss reflected by a combined ratio above 100%. Berkshire Hathaway's insurance subsidiaries have historically demonstrated this model. However, sustained underwriting losses gradually erode policyholder surplus and long-term financial strength ratings.
What causes a combined ratio to spike above 100%?
The most common drivers include major catastrophe events such as hurricanes, wildfires, and severe convective storms that trigger sudden surges in incurred losses; inadequate initial premium pricing that fails to cover realized claims; adverse reserve development on prior-year losses; rapid expense growth during expansion phases before written premium fully converts to earned premium; and systemic litigation or social inflation trends that significantly increase the cost of settling liability and casualty claims.
How do underwriters and financial analysts use the combined ratio?
Underwriters use the combined ratio to assess whether individual product lines and geographic territories are priced adequately, and to identify segments requiring rate increases or tighter risk selection criteria. Financial analysts compare combined ratios across peer groups to evaluate relative operational efficiency and pricing discipline. Regulators, including the NAIC, monitor insurer combined ratios as an early-warning indicator of financial stress, triggering enhanced capital and solvency scrutiny when ratios remain elevated for multiple consecutive quarters.