Updated July 2026
What Is Uninsured and Underinsured Motorist Coverage Insurance?
Uninsured motorist coverage (UM) and underinsured motorist coverage (UIM) protect you when another driver causes a crash but lacks insurance or carries limits too low to pay your full damages. UM pays when the at-fault driver has zero coverage. UIM pays when their liability limit falls short of your medical bills, lost wages, and vehicle repair costs. Both coverages step in only after the other driver's liability insurance—if any—has been exhausted, and they pay up to your selected UM/UIM limits.
- A driver with no insurance rear-ends you at a stoplight. You have $8,000 in medical bills and $5,500 in vehicle damage. The at-fault driver has zero coverage to pay your claim. Your UM coverage pays the $8,000 in medical costs up to your UM bodily injury limit, and your UIM property damage coverage—if you purchased it—pays the $5,500 vehicle repair after your collision deductible.
- Another driver causes a three-car pileup. Your medical bills total $40,000. The at-fault driver carries Ohio's minimum $25,000 bodily injury limit, which gets split among all injured parties—you receive $12,000. Your UIM coverage pays the remaining $28,000 up to your UIM limit, minus the $12,000 already paid by the other driver's liability policy.
- A vehicle sideswipes you on the highway and flees. You suffer $15,000 in injuries and $7,000 in vehicle damage. Because the driver is never identified, your UM coverage treats this as an uninsured motorist claim and pays your medical bills up to your UM limit. Your collision coverage—not UM—pays the vehicle damage after your deductible.
Who Needs Uninsured and Underinsured Motorist Coverage Insurance?
You should carry UM/UIM coverage if you cannot afford to pay your own medical bills and vehicle repairs after a crash caused by an uninsured driver. It's especially critical if you carry liability-only insurance with no collision or comprehensive coverage, because UM is often your only path to recovering vehicle damage costs when the at-fault driver has no insurance. Drivers in counties with high uninsured motorist rates—over 10 percent—face a one-in-ten chance the other driver won't have coverage.
Compare your UM/UIM premium to your health insurance deductible and collision deductible. If the combined deductibles exceed $2,000 and you lack $20,000 in liquid savings, the $10 to $15 monthly UM cost is justified. If your health plan and collision coverage already protect you and you can absorb a $10,000 loss, declining UM saves premium without meaningful risk.
How Much Does Uninsured and Underinsured Motorist Coverage Insurance Cost?
UM/UIM coverage typically adds $8 to $18 per month to an Ohio auto insurance premium, or $96 to $216 annually, depending on your selected limits and whether you include UM property damage.
- Your UM/UIM limit selection—higher limits cost more, but the premium difference between $25,000 and $100,000 UM coverage is often under $5 per month.
- Whether you add UM property damage coverage, which pays for vehicle repairs when the at-fault driver is uninsured—some carriers bundle this automatically, others charge separately.
- Your county's uninsured driver rate—counties with higher percentages of uninsured motorists see slightly higher UM premiums due to increased claim frequency.
- Your own driving record and claims history—carriers price UM coverage based on your likelihood of filing any claim, not just UM-specific claims.
- Whether you stack UM coverage across multiple vehicles on your policy, which multiplies your per-vehicle limit by the number of insured cars but raises the premium accordingly.