Quick Answer: 13% of US drivers are completely uninsured. UM/UIM coverage is your financial safety net when you're hit by one of them. In most states it costs only $8–$18/month — making it one of the best values in car insurance.
UM vs UIM — What's the Difference?
| Coverage | When It Applies | Example |
|---|---|---|
| UM (Uninsured Motorist) | At-fault driver has zero insurance | Driver with no policy rear-ends you at a red light |
| UIM (Underinsured Motorist) | At-fault driver has insurance but limits are too low | Driver with 25/50 limits causes $80,000 in injuries to you |
| UM Property Damage | Vehicle damage from uninsured driver | Uninsured driver totals your car in a parking lot |
Uninsured Driver Rates by State — 2026
The higher your state's uninsured driver rate, the more important UM/UIM becomes:
| State | Uninsured Driver Rate | UM Required? |
|---|---|---|
| Mississippi | ~29% | No (optional) |
| Michigan | ~25% | Yes |
| Tennessee | ~23% | No (optional) |
| Florida | ~20% | No (optional) |
| New Mexico | ~19% | No (optional) |
| North Carolina | ~7% | Yes (+ required) |
| National average | ~13% | Required in 22 states |
How Much Does UM/UIM Coverage Cost?
UM/UIM is one of the most cost-effective coverages in auto insurance. Adding 100/300 UM/UIM to a policy typically costs $8–$18/month — a small premium for significant financial protection.
| UM/UIM Limit | Typical Monthly Add-On Cost |
|---|---|
| 25/50 UM (state min equivalent) | $5–$10/mo |
| 50/100 UM | $8–$14/mo |
| 100/300 UM (recommended) | $10–$18/mo |
| 250/500 UM | $14–$25/mo |
Frequently Asked Questions — Uninsured Motorist Coverage
What is uninsured motorist coverage?
UM coverage pays your medical bills, lost wages, and vehicle repair when an at-fault driver has no insurance. UIM covers the gap when an at-fault driver has insurance but not enough to cover your damages.
Is UM/UIM coverage worth it?
Yes — almost universally. At $8–$18/month for 100/300 limits, it's one of the best values in insurance. With 13% of drivers uninsured nationally and much higher rates in states like Florida and Mississippi, the expected value is strongly positive.
Does UM cover hit-and-run accidents?
Yes, in most states. A hit-and-run driver is treated as an uninsured motorist under UM coverage. Physical contact with the fleeing vehicle is required in many states to file a UM claim — check your state's rules.
How much UM/UIM coverage should I carry?
Match your UM/UIM limits to your liability limits. If you carry 100/300/100 liability, carry 100/300 UM/UIM. This ensures symmetrical protection — you give the same level of coverage to others as you would receive from an uninsured driver.