Auto liability
Your state minimum vs what you own
Underinsured motorist calculator: what would UIM pay?
When the driver who hits you has too little insurance, underinsured motorist coverage can pay the difference. Enter your losses and both limits to see what each policy pays and what is left for you.
Result
Showing the worked example. Change any number to see your own result.
$45,000Paid by your UIM coverage
The at-fault driver's insurer pays $25,000 and your UIM pays $45,000, so your losses are covered.
- At-fault driver's insurer
- $25,000
- Your UIM
- $45,000
- Left for you
- $0
- Share of losses covered
- 100%
- At-fault driver's insurer
- Your UIM
- Left for you
View chart data as a table
| At-fault driver's insurer | Your UIM | Left for you | |
|---|---|---|---|
| Excess (add-on) state | $25,000 | $45,000 | $0 |
| Reducing (offset) state | $25,000 | $45,000 | $0 |
How the result is built
| Your losses | $70,000 |
|---|---|
| Paid by the at-fault driver's insurer | −$25,000 |
| Paid by your UIM coverage | −$45,000 |
| Left for you to cover | $0 |
Compare scenarios
Save up to 3 versions of your inputs and compare them side by side.
How to use this calculator
- Estimate your losses. Add medical bills, lost wages and other damages from the injury.
- Enter both limits. Use the at-fault driver's per-person bodily injury limit and your own per-person UIM limit.
- Choose your state's method. Excess (add-on) and reducing (offset) states calculate UIM differently.
- Read what is left. The result shows who pays what and any amount left uncovered.
What underinsured motorist coverage does
Many drivers carry only their state’s minimum liability limits. If one of them causes a crash that seriously injures you, their insurance may run out long before your bills do. Underinsured motorist (UIM) coverage, bought on your own policy, pays the difference up to your UIM limit. The Texas Department of Insurance describes it as paying if you’re hit by someone who didn’t have enough to pay your medical and car repair bills.
This calculator shows what the other driver’s insurer pays, what your UIM pays, and what would be left for you.
How the calculation works
States use one of two broad methods:
- Excess (add-on): UIM pays your losses above the other driver’s limit, up to your UIM limit.
UIM pays = min(losses − their payment, your UIM limit) - Reducing (offset): your UIM limit is reduced by what the other driver’s insurer paid.
UIM pays = min(losses, your UIM limit) − their payment
In both cases the at-fault driver’s insurer pays first, up to its per-person limit. Rules vary by state and policy, so treat this as an illustration and confirm how your state applies UIM.
Worked example
The calculator opens with this example: $70,000 of losses, an at-fault driver with a $25,000 per-person limit, and your $100,000 UIM limit in an excess state.
| Line | Calculation | Amount |
|---|---|---|
| Their insurer pays | Up to $25,000 | $25,000 |
| Your UIM pays | $70,000 − $25,000 | $45,000 |
| Left for you | $0 |
The same crash in a reducing state with a $50,000 UIM limit
| Line | Calculation | Amount |
|---|---|---|
| Their insurer pays | Up to $25,000 | $25,000 |
| Your UIM pays | $50,000 − $25,000 | $25,000 |
| Left for you | $70,000 − $50,000 | $20,000 |
In a reducing state, a UIM limit equal to the other driver’s limit pays nothing at all, which is why matching UIM to your own, higher liability limits matters there.
Choosing a UIM limit
| Your liability limits | UIM to consider |
|---|---|
| State minimum | At least the same, more if you can |
| 100/300 | 100/300 |
| 250/500 | 250/500 |
Some states let you “stack” UM/UIM limits across several vehicles for a higher premium. Virginia, for example, requires uninsured and underinsured coverage at the same limits as liability. Check your state’s rules with the auto liability checker.
What changes the answer
- Your state’s method (excess or reducing).
- Several injured people. Per-accident limits are shared among them.
- Other coverage. PIP, medical payments and health insurance may pay part of your losses first.
- Settlement rules. Many policies require you to notify your insurer before accepting the other driver’s limit.
Common mistakes
| Mistake | Better approach |
|---|---|
| Rejecting UIM to save a little premium | It protects you from other drivers’ choices |
| Buying UIM equal to the state minimum in a reducing state | It may pay nothing |
| Settling with the other insurer without telling yours | Can jeopardize your UIM claim |
Next steps
Read our guide to uninsured motorist coverage for how claims work, and use the umbrella insurance calculator to see whether you need protection above your auto limits.
Questions people ask
What is underinsured motorist coverage?
Coverage on your own policy that pays your injury losses when the at-fault driver has liability insurance but not enough to cover them, up to your UIM limit.
How is underinsured motorist coverage calculated?
In excess or add-on states, UIM pays your losses above the other driver's limit, up to your UIM limit. In reducing or offset states, the other driver's payment is subtracted from your UIM limit.
How much UIM coverage should I have?
A common approach is to match your own bodily injury liability limits, for example 100/300 of UIM if you carry 100/300 liability.
Is UIM the same as uninsured motorist coverage?
They are related. Uninsured motorist coverage applies when the at-fault driver has no insurance; underinsured applies when they have too little. Many policies sell them together.
Is UIM required in my state?
Some states require it, others require insurers to offer it. Our auto liability checker shows which coverages each state requires.
Does UIM cover my car?
UIM bodily injury covers injuries, not vehicle damage. Collision or uninsured motorist property damage, where available, covers your car.
Do I need the other driver's insurer to pay first?
Usually the at-fault driver's insurer pays its limit first, and you must follow your policy's notice and consent rules before settling. Ask your insurer before accepting a settlement.
Sources
- Auto Insurance — National Association of Insurance Commissioners (NAIC), accessed
- Auto insurance guide — Texas Department of Insurance, accessed
- Insurance Requirements — Virginia Department of Motor Vehicles, accessed
Educational information, not insurance, legal or financial advice. Coverlee does not sell insurance. How we calculate
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