Stacked vs. Unstacked car insurance

Stacked insurance typically applies to uninsured and underinsured motorist coverage. Stacking means that you can combine coverage limits for multiple vehicles.

A coverage limit is the maximum amount your insurer will pay toward a covered claim. So, combining separate coverage limits into one higher limit can offer greater protection in case you're involved in a car accident with an uninsured or underinsured driver.

Uninsured and underinsured motorist coverage

Uninsured motorist coverage (UM) helps pay for your accident-related expenses if you're hit by a driver without car insurance. Underinsured motorist coverage (UIM) helps pay for your expenses if the at-fault driver's insurance is insufficient to cover your bills after an accident.

There are several types of UM and UIM coverage:

• UM and UIM bodily injury coverage help pay your medical expenses after an accident with an uninsured or underinsured driver. These coverages may be required or optional, depending on your state's laws.
• UM and UIM property damage coverage help pay to repair or replace your property if it's damaged by an uninsured or underinsured driver. These coverages may not be available on your car insurance policy, depending on your state's laws.

Note that stacking only applies to the bodily injury portion of the coverage. You cannot stack property damage coverage limits.

How stacking works

State laws may require stacking, allow stacking or not allow stacking at all. And, even if the law allows stacking, insurers may put anti-stacking wording into their policies.

Depending on the laws where you live, your insurance may be stacked:

• On a single car insurance policy insuring two or more vehicles
• Across two or more separate car insurance policies in your name

Stacking on one car insurance policy

Some states allow stacking UM and UIM coverage limits within a single car insurance policy.

For example: You insure two vehicles on the same policy. You have uninsured motorist bodily injury (UMBI) coverage limits of $25,000 on each vehicle.

Stacking your coverage within that policy would increase your UMBI limits to $50,000 per accident. So, if you were hit by a driver without insurance, your insurer would help pay your medical expenses after the accident, up to $50,000.

Stacking across multiple car insurance policies

Some states allow stacking UM and UIM coverage limits across multiple car insurance policies.

For example: Your name is listed on two car insurance policies. One policy is for a vehicle you own, and another policy is for the vehicle of a family member in your household. Your policy has a UMBI coverage limit of $30,000. Your family member's policy with your name listed has a UMBI limit of $25,000.

If you choose to stack across the two policies, it would increase your UMBI coverage limit to $55,000. So, if you were hit by an uninsured driver, your insurer would help pay your medical bills after the accident, up to $55,000.

Advantages of stacking

Stacking allows you to combine UM and UIM coverage limits on multiple vehicles, thereby increasing your protection against accident-related expenses. Higher coverage limits mean you may have to pay less out of your own pocket toward a covered claim.

Disadvantages of Stacking

Generally, you'll pay higher premiums for higher coverage limits. This means when you stack UM and UIM limits, you could pay more for that coverage.

States that allow stacking

As of May 2023, 32 states may allow stacking. Keep in mind that your insurer may not offer stacked coverage even if the state allows it.

Unstacked insurance means that your UM and UIM coverage limits for multiple vehicles are not combined.

Advantages of unstacked insurance

Premiums for unstacked insurance may be lower than premiums for stacked coverage. That's because stacking coverage increases the overall limit, or the amount that your insurer might have to pay toward a covered claim. Remember, the higher the limit, the more costly your coverage may be (and vice versa).

Disadvantages of unstacked insurance

If your insurance is unstacked, you may be at higher risk of paying out of pocket for accident-related expenses.

Say you're injured when an uninsured driver hits your car. You have unstacked UM coverage with a limit of $25,000. If your medical bills exceed $25,000, you may have to pay the rest out of your own pocket. If you had stacked UM coverage, however, you may be able to draw from the UM coverage you had on other vehicles to help pay for the rest of your medical expenses.

Even if your insurance is not stacked, you have the option of increasing your UM/UIM limit up to the amount your state allows to help increase your protection.