Insurance Loss Ratio Calculator

Background.

A reader arrives at Insurance Loss Ratio Calculator to divide incurred claims plus loss-adjustment expense by earned premium for one reporting period. Loss ratio is an insurer underwriting measure; earned premium aligns revenue with the coverage period and incurred loss includes claim estimates. For that reason, this page names its convention as “loss ratio = incurred claims and loss-adjustment expense / earned premium.”

The editable entries are incurred claims and loss-adjustment expense, earned premium. Use values from the document or measurement that governs this insurance loss ratio question; the defaults are only the worked fixture below. Before relying on the number, check this insurance loss ratio boundary: expense ratio, reserve development, reinsurance and combined ratio are separate, so a low loss ratio is not profit by itself.

NAIC Glossary of Insurance Terms; loss ratio, earned-premium and incurred-loss definitions documents the convention or governing rule used here. The insurance loss ratio output is a transparent scenario under those facts: it does not manufacture an unentered market price, professional determination, carrier quote, legal eligibility finding or locally adopted code value.

What is insurance loss ratio calculator?

Insurance Loss Ratio is the relationship behind this decision: loss ratio is an insurer underwriting measure; earned premium aligns revenue with the coverage period and incurred loss includes claim estimates. On this page it means loss ratio = incurred claims and loss-adjustment expense / earned premium. Expense ratio, reserve development, reinsurance and combined ratio are separate, so a low loss ratio is not profit by itself; that is the line between the reported quantity and a broader insurance analysis.

How to use this calculator.

1. 01Confirm that “loss ratio = incurred claims and loss-adjustment expense / earned premium” matches the insurance loss ratio convention you need.
2. 02Replace the fixture values for incurred claims and loss-adjustment expense, earned premium with dated values from the governing record.
3. 03Keep all currencies, measurement units and time periods on the same basis before calculating.
4. 04Read insurance loss ratio together with this boundary: Expense ratio, reserve development, reinsurance and combined ratio are separate, so a low loss ratio is not profit by itself.

The formula.

The calculation uses loss ratio = incurred claims and loss-adjustment expense / earned premium. In this insurance loss ratio model, the entered terms are incurred claims and loss-adjustment expense, earned premium. Loss ratio is an insurer underwriting measure; earned premium aligns revenue with the coverage period and incurred loss includes claim estimates, which is why the relationship is presented under this name rather than as a universal alternative. Expense ratio, reserve development, reinsurance and combined ratio are separate, so a low loss ratio is not profit by itself. Calculations keep full decimal precision through the relationship and round only the returned display values.

A worked example.

Frequently asked questions.

References& sources.

1. [1]NAIC Glossary of Insurance Terms; loss ratio, earned-premium and incurred-loss definitions. Retrieved 2026-08-07. access: open unless marked otherwise.
2. [2]National Association of Insurance Commissioners. Consumer insurance resources. Retrieved 2026-08-07. independence: primary; access: open.
3. [3]U.S. Census Bureau. Quarterly financial report. Retrieved 2026-08-07. independence: secondary-check; access: open.