Understanding Combined Ratio
How we calculate. Combined % = (losses + underwriting expenses) ÷ earned premium × 100. See our methodology and accuracy policy .
Real-world scenario: A typical Combined Ratio case uses incurred losses 6500000 and underwriting expenses 2800000. Enter the same figures below to reproduce the worked path.
What is Combined Ratio?
The headline underwriting result: under 100% usually means underwriting profit before investment income; over 100% means an underwriting loss.
- Losses + expenses in the numerator
- Earned premium denominator
- < 100% ≈ underwriting profit (before investment)
The Formula
Worked Example
Common Use Cases
- Carrier dashboards: underwriting result
- Segment compare: lines of business
- Management targets: COR goals
Pro Tips
- Align expense inclusions (LAE vs ULAE)
- Separate investment income from COR
- Label calendar vs accident year
| Scenario | When to use |
|---|---|
| Percent of a number | Finding a part of a whole (tax, tip, score) |
| Percent change | Comparing old vs new values |
Limitations: Combined Ratio results are educational insurance and agency planning aids—not underwriting, actuarial, claims, or financial advice. Confirm statutory definitions with your carrier, regulator, and finance teams.
Common mistakes
- Swapping part and whole: The denominator must be the full total, not a subset.
- Rounding too early: Carry extra decimal places through multi-step work before rounding the final percent.
- Mixing percent and decimal forms: Enter rates in the format the calculator labels expect.
When to use this calculator
- Use this page when your wording matches combined ratio and the form labels on screen.
- Use percent of a number for “what is X% of Y?” problems.
- Use number is what percent when you know part and whole and need the percent.
Still unsure about combined ratio? Start with the quick answer above, then open the linked calculator that matches your wording.
❓ Frequently Asked Questions
How do I use this combined ratio calculator?
For combined ratio, enter the values labeled on the form, then press Calculate. Compare the result to the worked example on this page.
What formula does this page use?
See the quick answer and formula box above for combined ratio—the same percentage calculator expression is applied to your inputs.
What if my result looks wrong?
When checking combined ratio, re-check part vs whole (or rate vs base), rounding, and whether percents were entered as 25 rather than 0.25 when the form expects percents.
Authoritative References
For insurance ratio and reporting concepts, consult:
- NAIC — U.S. insurance regulatory resources
- Casualty Actuarial Society — actuarial education resources
- Insurance Information Institute — industry explainers