Updated July 2026
What Is Uninsured and Underinsured Motorist Coverage Insurance?
Uninsured motorist coverage (UM) and underinsured motorist coverage (UIM) protect you when the driver who caused your accident doesn't have insurance or doesn't have enough to cover your medical bills, lost wages, and vehicle repairs. UM kicks in when the at-fault driver has zero insurance. UIM covers the gap when their liability limits fall short of your actual damages. Both coverages use your own policy limits — if you carry $100,000 in UM/UIM and the other driver has $30,000 in liability, UIM pays up to $70,000 to bridge the shortfall.
- You're stopped at a red light when a driver with no insurance slams into your car at 40 mph. You suffer a concussion and neck injury requiring $18,000 in medical treatment and miss three weeks of work, losing $4,500 in wages. The at-fault driver has no policy to file against. Your $50,000 UM coverage pays the full $22,500 in medical bills and lost income. Without UM, you'd be suing an uninsured driver with no assets to collect from.
- A driver carrying North Carolina's minimum $30,000 bodily injury liability runs a stop sign and T-bones your vehicle. You sustain a fractured pelvis and require surgery, racking up $85,000 in medical expenses. Their liability policy maxes out at $30,000. Your $100,000 UIM coverage pays the remaining $55,000. Without UIM, you'd absorb that $55,000 shortfall yourself or pursue a lawsuit that may never collect.
- Someone sideswiped your parked car overnight and fled. You have collision coverage with a $1,000 deductible, but you also added uninsured motorist property damage (UMPD) with a $250 deductible. The $3,200 repair bill gets covered under UMPD, saving you $750 compared to filing under collision. UMPD is a separate add-on to standard UM/UIM and specifically covers vehicle damage from uninsured or hit-and-run drivers.
Who Needs Uninsured and Underinsured Motorist Coverage Insurance?
You should carry UM/UIM if you drive frequently in areas with high uninsured driver rates, if your health insurance has high deductibles or doesn't cover auto accident injuries fully, or if you're the primary income earner in your household and can't afford weeks of unpaid recovery after an accident. It's especially valuable if you carry liability-only or minimum coverage and lack collision or comprehensive to cover your own vehicle.
Match your UM/UIM limits to your liability limits — if you carry $100,000 in liability, carry $100,000 in UM/UIM so you're protected at the same level you protect others. If your health insurance deductible exceeds $3,000 or doesn't cover auto accidents, UM/UIM becomes essential. Stacking makes sense if you insure multiple vehicles and want maximum protection, but costs rise significantly.
How Much Does Uninsured and Underinsured Motorist Coverage Insurance Cost?
Adding UM/UIM coverage typically costs $8 to $18 per month, or $96 to $216 annually, depending on your selected limits and whether you stack coverage across multiple vehicles.
- Your UM/UIM limits — matching your liability limits costs more but closes coverage gaps if you're hit by an underinsured driver with serious injuries.
- Stacking election — stacked UM/UIM multiplies your per-vehicle limit by the number of insured vehicles, doubling or tripling your available coverage but raising premiums 30 to 50 percent.
- Uninsured motorist property damage (UMPD) endorsement — adding UMPD for hit-and-run vehicle damage typically adds $3 to $6 per month.
- Your county's uninsured driver rate — counties with higher uninsured motorist rates see slightly higher UM/UIM premiums due to elevated claim frequency.
- Your liability limits — carriers often require UM/UIM limits to match or stay below your liability limits, so higher liability coverage indirectly raises UM/UIM cost.
- Claims history — prior UM claims can increase premiums at renewal, though less severely than at-fault liability claims.