Stacked vs. unstacked car insurance

You can increase your protection from uninsured and underinsured drivers by combining, or stacking, your insurance coverage.

Anna SwartzAndrew Hurst

By 

Anna Swartz

Anna Swartz

Managing Editor & Auto Insurance Expert

Anna Swartz is a managing editor and auto insurance expert at Policygenius, where she oversees our car insurance coverage. Previously, she was a senior staff writer at Mic.com, as well as an associate writer at The Dodo.

 & Andrew Hurst

Andrew Hurst

Senior Editor & Licensed Auto Insurance Expert

Andrew Hurst is a senior editor and a licensed auto insurance expert at Policygenius. His work has also been featured in The New York Times, The Wall Street Journal, Forbes, USA Today, NPR, Mic, Insurance Business Magazine, ValuePenguin, and Property Casualty 360.

Updated February 28, 2022 | 3 min read

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Stacked insurance is a way of increasing your car insurance policy's uninsured and underinsured motorist coverage. To stack your insurance, you would combine the amount of uninsured coverage from multiple vehicles or multiple policies — as long as both policies are in your name.

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Stacking your car insurance coverage is a good way to increase the protection of your policy, but you can only stack coverage in 32 states. However, if you have more than one car or live in a place where there are a lot of uninsured drivers or low required limits of liability, stacked insurance could be the best option for you.

Key Takeaways

  • Stacked insurance increases your car insurance policy's uninsured and underinsured motorist protection.

  • You can get stacked insurance by combining the coverage you get from insuring more than one vehicle with one or more policies.

  • Not every state allows you to get stacked insurance — stacking is allowed in 32 states.

  • You should consider stacked insurance if you live in a state with a lot of uninsured drivers, or where the required limits for insurance are relatively low.

What is stacked vs. unstacked insurance?

When you stack your car insurance, you combine the uninsured and underinsured motorist coverage from two vehicles, insured by one or more policies, to increase your protection. Your uninsured or underinsured motorist coverage (UM/UIM) pays for damage caused by drivers who either don't have car insurance or don’t have enough to pay for the repairs your car needs after an accident.

There are two ways that you can get stacked uninsured motorist coverage. You can either stack your coverage vertically or horizontally depending on how many policies you have.

  • Vertically stacked insurance: If you have multiple cars on one insurance policy, you can combine the total amount of uninsured coverage you have to make a claim for a single vehicle.

  • Horizontally stacked insurance: If you have more than one car insurance policy with the same company, you can combine the total UM/UIM coverage to make a claim for damage to one vehicle.

Unstacked insurance, on the other hand, is just the standard amount of UM/UIM protection that you get when you don't combine coverage limits. Although the cost to insure your car is cheaper with unstacked instead of stacked insurance, with unstacked coverage, you're protected up to your policy's per-car or per-policy limits — and no more.

How does stacked insurance work?

Let's say that you've insured more than one car on the same insurance policy. Both vehicles have $25,000/$50,000 of uninsured motorist bodily injury liability coverage, meaning $25,000 per person and a total of $50,000 for the entire accident. 

In this case, with stacked insurance you’d be covered for up to $50,000 per person after an accident. If the uninsured driver caused $45,000 of injuries, you'd be covered. However, with an unstacked policy, you could be responsible for paying $20,000 out of pocket after a similar accident.

Is stacked or unstacked insurance better?

Because stacking your uninsured and underinsured motorist coverage significantly increases your protection, it's a good idea to get stacked insurance if it's available to you and you can afford it. Despite being slightly more expensive, stacking your insurance is a good way to avoid high, unexpected bills after an accident.

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Who can get stacked insurance?

Not everyone who wants stacked insurance can get it. First, in order to stack your uninsured motorist coverage, you have to have at least two cars. If you only have one vehicle and still want more coverage against uninsured and underinsured drivers, just increase your policy's coverage limits instead.

You also have to live in a state that allows you to stack your insurance coverage. Twenty-two states allow drivers to get stack your car insurance across cars on the same policy (vertically) or across two policies from the same company (horizontally):

There are also 10 states that allow drivers to get stacked insurance, but only across two policies insured by the same company (horizontally). The states that only allow horizontal stacking are:

How do you get stacked insurance?

If you live in a state where you can get stacked insurance, you may need to confirm that you want to stack your coverage when you buy a policy — depending on the insurance company. You may also need to reject stacked insurance in writing if you don't want the coverage.

That said, you should also ask your insurance provider whether you have stacked insurance coverage if you're not sure. Even though you may live in a state where stacked coverage is allowed, your insurer may not have to offer it, as long as they make it clear in your insurance agreement that your coverage cannot be stacked.

Do you need stacked insurance?

Stacked insurance isn’t required, but you should consider getting stacked insurance if you have two cars or two policies and live in a state where stacked insurance is allowed. Stacked insurance could be an especially good idea if you live in a state where there are a high number of uninsured drivers, like Florida, where more than one in four drivers are uninsured.

If you live in a state with low minimum requirements for car insurance, you should also consider getting stacked insurance. While a driver carrying low amounts of liability coverage isn’t technically uninsured, they might not have enough coverage to pay for your bills after an accident, and you could be left paying for your injuries or your car's damage yourself.

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Frequently Asked Questions

Is stacked insurance required in any state?

Stacked insurance is not required in any state, but uninsured and underinsured motorist coverage sometimes is. If you live in a state where you're required to get UM/UIM coverage and where you can stack your coverage, you should consider doing so if you have more than one car.

What does it cost to stack insurance?

Usually, uninsured and underinsured motorist coverage only makes up a small portion of your total car insurance premium. Even as you increase the amount of UM/UIM coverage, your rates won't often climb significantly. Similarly, stacked uninsured motorist coverage costs more than an unstacked policy, but the price increase won't usually be significant.