Updated July 2026
What Is Uninsured and Underinsured Motorist Coverage Insurance?
Uninsured motorist coverage (UM) pays when the driver who hit you has no insurance. Underinsured motorist coverage (UIM) pays when their liability limits are too low to cover your damages. Both protect you from out-of-pocket costs when the at-fault party can't pay. UM/UIM typically covers medical expenses, lost wages, pain and suffering, and vehicle damage depending on your policy structure.
- You're rear-ended at a stoplight. The other driver has no insurance. You have $8,000 in medical bills and $4,500 in vehicle damage. Your UM coverage pays both, minus your deductible if your policy includes a UM property damage deductible. Without UM, you'd pay everything yourself or sue the uninsured driver — who likely has no assets to collect.
- A driver runs a red light and hits you. They carry the state minimum liability — $25,000 per person. Your medical bills reach $45,000. Their liability pays the first $25,000. Your UIM coverage pays the remaining $20,000. Without UIM, you'd be responsible for that $20,000 gap.
- You're sideswiped on I-25 and the driver flees. You have $6,000 in vehicle damage and $3,000 in medical costs. Your UM coverage treats this as an uninsured motorist claim and pays both, subject to your policy limits and deductible. Without UM, you'd file under collision coverage for the vehicle damage only — medical costs would be out of pocket.
Who Needs Uninsured and Underinsured Motorist Coverage Insurance?
Carry UM/UIM if you drive frequently in areas with high uninsured driver rates, if your health insurance has high deductibles or excludes auto accident injuries, or if you're financing a vehicle and want protection beyond collision coverage. It's especially valuable if you carry liability-only coverage on an older vehicle — UM gives you injury protection even when you skip comprehensive and collision.
Compare your UM/UIM limits to your liability limits — most agents recommend matching them. If you carry $100,000 liability per person, carry $100,000 UM. Decide whether to stack coverage if you insure multiple vehicles. Stacking costs more but multiplies your available limit if you're seriously injured. Check whether your policy includes UMPD or only UM bodily injury — if you carry liability-only, UMPD is your only vehicle damage protection when an uninsured driver hits you.
How Much Does Uninsured and Underinsured Motorist Coverage Insurance Cost?
UM/UIM coverage typically adds $8–$18 per month to your premium, or approximately $95–$215 annually, depending on your selected limits and whether you stack coverage across multiple vehicles.
- Selected UM/UIM limits — higher limits cost more, but the incremental cost from $25,000 to $100,000 is often under $5 per month.
- Stacking election — stacked UM/UIM multiplies your per-vehicle limit by the number of insured vehicles, increasing both protection and cost by roughly 15–30%.
- Uninsured motorist property damage (UMPD) inclusion — adding UMPD to cover vehicle damage increases cost by approximately $3–$8 per month.
- Your county's uninsured driver rate — carriers price UM/UIM higher in counties with above-average uninsured motorist claim frequency.
- Bodily injury vs combined single limit structure — policies with separate UM bodily injury and UMPD endorsements may cost slightly more than combined structures.