Uninsured/Underinsured Motorist Coverage Explained
Uninsured/underinsured motorist coverage is one of the most misunderstood parts of an auto policy — and also one of the most important. It protects you in a situation you can’t control: getting hit by someone who either has no insurance at all, or doesn’t have enough to cover what your accident actually costs. Here’s how it works and why it’s worth understanding before you need it.
What Uninsured/Underinsured Motorist Coverage Actually Covers
This coverage pays for your injuries and, in many states, your vehicle damage when the at-fault driver either has no insurance or doesn’t have enough insurance to cover the full cost of the accident. It essentially steps in to fill the gap the other driver’s policy leaves behind.
It’s split into two related parts: uninsured motorist (UM) coverage applies when the other driver has no insurance at all, while underinsured motorist (UIM) coverage applies when they have insurance, but their liability limits are too low to cover your damages.
Why This Coverage Exists in the First Place
Despite insurance being legally required in nearly every state, a meaningful share of drivers on the road are uninsured — the Insurance Information Institute tracks the exact rate by state — or carry only the state-minimum liability limits, which can be surprisingly low. If one of these drivers causes an accident that injures you, their policy — or lack of one — may not come close to covering your medical bills, lost wages, or vehicle repair costs.
Since you can’t control what insurance the other driver carries, UM/UIM coverage is designed to protect you from a risk that’s entirely outside your hands.
Is It Required, or Optional?
This varies significantly by state. Some states require insurers to include it unless you specifically decline it in writing, while others make it fully optional or don’t require it at all. Because the rules differ so much, it’s worth checking your specific state’s requirement rather than assuming — and it’s worth reviewing alongside your liability and full coverage limits at the same time, since they work together.
Even in states where it’s optional, many insurance professionals consider it one of the more valuable coverages to keep, given how directly it protects you personally rather than just meeting a legal minimum.
What Happens If You Decline It
If your state allows you to decline UM/UIM coverage and you do, you’re accepting that if an uninsured or underinsured driver hits you, you may be responsible for covering your own medical bills and repair costs beyond what the at-fault driver’s limited (or nonexistent) insurance provides. Health insurance may cover some medical costs, but it won’t typically cover vehicle damage or lost income the way UM/UIM coverage can.
How Much Coverage Should You Consider?
A common approach is to match your UM/UIM limits to your liability limits, on the reasoning that the protection you’d want for yourself should be at least as strong as what you’re required to offer others. Beyond that general guideline, the right amount really depends on your own finances, health coverage, and risk tolerance — this is a conversation worth having directly with your insurance agent rather than guessing, alongside other optional coverages like gap insurance if you’re financing your vehicle.
Frequently Asked Questions
Is uninsured motorist coverage the same in every state?
No. Requirements and rules vary significantly — some states require insurers to offer or include it by default, others make it fully optional, and the specifics of what it covers (bodily injury only, or also property damage) differ as well. Check your state’s specific rules or ask your insurer directly.
Does UM/UIM coverage raise my premium significantly?
The cost varies by insurer and state, and there’s no universal figure since pricing depends on many individual factors. Getting a direct quote comparison with and without this coverage from your insurer is the only accurate way to see the cost difference for your specific policy.
What’s the difference between uninsured and underinsured motorist coverage?
Uninsured motorist coverage applies when the at-fault driver has no insurance at all. Underinsured motorist coverage applies when they do have insurance, but their coverage limits aren’t enough to fully pay for your damages. Many policies bundle both together under a single UM/UIM coverage line.
This article is for general informational purposes only and does not constitute insurance, legal, or financial advice. Insurance rates, coverage requirements, and eligibility vary by state, insurer, and individual circumstances. Always confirm details directly with a licensed insurance agent or your insurance provider before making coverage decisions.