Stacked vs. Unstacked Auto Insurance: What's the Difference?

Your insurance coverage needs will help you choose

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If you own more than one car, there could be a way for you to combine liability coverage limits on multiple vehicles to protect yourself from damage caused by an uninsured or an inadequately insured person. You can do that using stacked insurance coverage.

Learn more about stacked auto insurance coverage and how it compares to unstacked, or regular, auto insurance.

What's the Difference Between Stacked and Unstacked Insurance?

Stacked Insurance Unstacked Insurance
Offers broader coverage Offers regular coverage
More expensive Less expensive
Not allowed in every state Available in every state

Understanding UM and UIM Coverage

First of all, stacked insurance becomes an option if you own and insure multiple vehicles. If you are in an expensive accident, stacked coverage means that even if the other driver is uninsured, you will still be covered for double the amount of one policy alone.

Uninsured motorist (UM) coverage pays what the other party’s insurance should have paid if the driver who caused the accident is uninsured. A UM policy covers bodily injury and—depending on the policy—can also cover the damaged property.

Underinsured motorist (UIM) coverage protects you against other drivers on the road. If someone causes an accident that creates more damage than their insurance policy covers, UIM coverage will protect you from the difference.


According to a 2021 report, approximately one in eight drivers does not have car insurance. Uninsured motorist coverage protects you from paying the price.

Like any insurance coverage, there are set limits to how much damage the policy will cover. That’s where stacked coverage comes in: If you insure multiple vehicles, you can “stack” the coverage limits so that they are much higher for any one given accident than they would be if you only insured one vehicle.

Unstacked insurance is essentially any regular auto insurance policy. Of course, auto insurance policies can vary greatly, but if you don't stack your coverage, your policy is unstacked. Your coverage is only what's listed on the declarations page of your policy. If you get into an accident, your coverage level will not be as high as it would have been with a stacked policy.

Also, if you only own or insure one car, stacked insurance will not be an option. That means you will have an unstacked or regular auto insurance policy.


Just like any insurance policy, the more coverage you have, the more expensive the policy will be. Stacking your uninsured motorist coverage is more expensive than purchasing separate and unstacked coverage since you are doubling your coverage limit. 

On the other hand, the cost of an unstacked/regular auto insurance policy will be lower than a stacked one. Keep in mind, though, that you may end up paying more out-of-pocket if you end up in an accident with an uninsured or underinsured driver.


Some states limit the number of policies you can stack or your ability to do so at all. This can also get tricky if other people in your family are the ones driving the vehicle, so make sure to talk to a qualified insurance agent.

No matter where you live, you should be able to find regular or unstacked auto insurance fairly easily from a variety of insurance companies.

Example of How Stacked Insurance Works

Here's a situation in which it could be important. Let's say you are in an accident where you are not at fault. The other driver who caused the accident does not have insurance, and the damage to you or your vehicle exceeds the uninsured motorist coverage you have purchased on one of your vehicles.

If you have purchased uninsured or underinsured motorist coverage on multiple vehicles, you will be covered up to a certain limit on each vehicle. But what if you are in an accident that causes $150,000 worth of damage and your coverage limit was $100,000?


If you only own one vehicle that has uninsured motorist coverage, you are on the hook for this damage. If you own two vehicles with unstacked motorist coverage, you are also out of luck.

If you have stacked your auto insurance coverage, you can “borrow” from the other vehicle’s coverage, and you won’t have to pay a penny out of pocket.

Which Is Right for You?

If you want to increase your uninsured/underinsured motorist insurance coverage, then stacked coverage might be the right option for you. Of course, the more coverage you have the more expensive your policy will be. But if you choose to stack your insurance coverage, you're doing it with the worst-case scenario in mind—not the best. In the event of an accident with an uninsured or underinsured driver, your stacked insurance will help keep you from paying out-of-pocket costs.

If you are less concerned about this type of situation, or you only own/insure one vehicle, then a regular, unstacked auto insurance policy might be right for you.

The Bottom Line

Auto insurance is important, whether you end up with a stacked or unstacked policy. If you're not sure which is right for you, you can always talk to your insurance agent. If you insure multiple vehicles, they may be able to help you decide whether paying for a stacked policy makes sense for you.

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The Balance uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Insurance Research Council. "One in Eight Drivers Uninsured," Page 1.

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