Settlement Calculator

Underinsured motorist (UIM) claim calculator

The driver who hit you didn't carry enough insurance to cover your losses — so what can your own underinsured motorist (UIM) coverage actually add? This estimates it and applies your state's offset-vs-add-on rule, the part that changes the answer by thousands. Free, private, no sign-up.

Why this is hard to find: the only "UIM calculators" online are law-firm lead forms or black-box tools. The actual math is simple — but it hinges on a state rule (offset vs add-on) most pages gloss over. We show both outcomes and flag your state's likely rule, with no contact form.
1 Your state

UIM rules vary a lot by state — we apply yours.

2 Your total damages

Not sure? Estimate it with the calculator first →

3 The at-fault driver's coverage

Usually their per-person bodily-injury limit — often the state minimum.

4 Your UM/UIM limit

On your insurance declarations page — look for the "UM/UIM" or "Uninsured/Underinsured Motorist" line.

Everything stays in your browser — no email, no account.

UIM in plain English

UIM kicks in when the at-fault driver has insurance but not enough to cover your losses. It pays from your own policy — coverage you already bought for exactly this. Two things decide how much it adds: your UIM limit, and whether your state treats UIM as offset (limit reduced by the at-fault payment) or add-on (pays on top). Unlike MedPay/PIP, UIM requires proving the other driver was at fault.

Frequently asked

How is a UIM claim calculated?

UIM covers the gap between your damages and the at-fault driver's available coverage, up to your own UIM limit — but the measurement depends on your state. In offset states your UIM limit is reduced by what the at-fault insurer paid; in add-on states UIM pays on top, up to your full limit. Either way, you must prove the other driver was at fault.

Does UIM stack on top of the at-fault driver's policy?

Depends on your state. In add-on/excess states, yes. In offset states, your UIM limit is reduced by the at-fault payment, so it doesn't simply stack. ("Stacking" can also mean combining the UM/UIM limits of multiple vehicles/policies you own — allowed in some states, prohibited in others, often policy-dependent.)

Do I have to exhaust the other driver's policy first?

Often yes — many states and policies require you to use up the at-fault driver's limits and get your insurer's written consent before settling. Settling too early can void your UIM claim, so confirm the steps before signing any release.

Will my premium go up if I use my UIM coverage?

A UIM claim when you weren't at fault generally shouldn't raise rates the way an at-fault claim can, though practices vary by insurer and state. It's coverage you already paid for, made for exactly this situation.

Important disclaimer

This is a general estimate for informational purposes only and is not legal advice. UM/UIM law varies by state and the offset-vs-add-on outcome can depend on your specific policy language, the coverage option you bought, and recent changes in the law. Confirm your coverage on your declarations page and, for a serious or disputed claim, consult a licensed attorney in your state. See our full Disclaimer.

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