Uninsured and Underinsured Motorist Coverage Explained (2026)

Uninsured motorist (UM) and underinsured motorist (UIM) coverage pays for your injuries and, depending on your policy, vehicle damage when the at-fault driver either has no insurance or not enough to cover your costs — and it's remarkably cheap for how much financial exposure it closes. For the full situational breakdown, see our special situations pillar guide.

What UM and UIM each cover

What it actually costs

UM/UIM coverage averages just $33 to $76 a year at 25/50 limits, or $86 to $134 a year at higher 100/300 limits — a small addition to most policies relative to the financial exposure it closes. Some policies also use UM/UIM to cover a rental car or your collision deductible after a hit-and-run, depending on the specific policy language.

Where it's actually required

Twenty-two states require some form of UM or UIM coverage, though the specific requirement varies — some mandate only UM, others require both. States requiring both UM and UIM include Illinois, Kansas, Missouri, New Hampshire, New York, South Carolina, West Virginia, and Washington, D.C. In the states where it's optional, insurers are generally still required to offer it, but you have to actively decline it in writing — many drivers unknowingly waive it by not reading that section of their policy paperwork.

Why it's worth adding even where it's optional

A meaningful share of drivers on the road carry no insurance at all or only the state minimum, which is frequently far below what a serious injury actually costs. Without UM/UIM, your only recourse against an uninsured or underinsured at-fault driver is a personal lawsuit — often difficult or impossible to collect on if that driver has no meaningful assets, which is frequently correlated with why they were uninsured in the first place.

How much UM/UIM coverage should you carry?

A common rule of thumb is matching your UM/UIM limits to your own liability limits — if you've sized your liability coverage to protect your assets (see our liability coverage calculator), your UM/UIM should generally match, since the financial exposure from being hit by an uninsured driver is just as real as the exposure from causing an accident yourself.

Frequently asked questions

What's the difference between uninsured and underinsured motorist coverage?+

Uninsured motorist (UM) coverage applies when the at-fault driver carries no liability insurance at all. Underinsured motorist (UIM) coverage applies when the at-fault driver has insurance, but their limits aren't enough to cover your full medical and repair costs.

How much does uninsured motorist coverage cost?+

It's one of the cheapest coverage additions available — averaging $33 to $76 a year at 25/50 limits, or $86 to $134 a year at higher 100/300 limits, according to 2026 industry rate data.

Is uninsured motorist coverage required by law?+

In 22 states, yes, in some form. States requiring both UM and UIM coverage include Illinois, Kansas, Missouri, New Hampshire, New York, South Carolina, West Virginia, and Washington, D.C. In other states it's optional but insurers must offer it.

Should I carry UM/UIM coverage even if my state doesn't require it?+

Most financial advisors and agents recommend it given how cheap it is relative to the risk — a meaningful share of drivers on the road carry no insurance or only the state minimum, and without UM/UIM your only recourse is a personal lawsuit against that driver.