Stacked vs. Unstacked Car Insurance


Enter your ZIP code to get started

Shield

Free. Simple. Secure.

Key Takeaways

blueCheck icon

Stacked insurance combines uninsured motorist coverage from multiple vehicles or policies to give you more financial coverage after an accident.

blueCheck icon

Stacking insurance is most useful if you own multiple cars, are listed on several policies or live in a state with many uninsured drivers.

blueCheck icon

Some states don’t allow stacking, and others limit it to either vertical (one policy) or horizontal (multiple policies) stacking.

Compare Auto Insurance Rates

Ensure you're getting the best rate for your auto insurance. Compare quotes from the top insurance companies.

Why do we need ZIP code?

Stacked Car Insurance: What Is It?

Stacked car insurance lets you combine uninsured motorist (UM) coverage limits across multiple vehicles under the same policy or across multiple policies that list your name. For instance, if you have a $25,000 UM limit on one car and $50,000 on another, stacking gives you up to $75,000 in total coverage if you're injured by an uninsured driver. 

There are two main types of insurance stacking: stacking within one policy and stacking across multiple policies, also known as vertical and horizontal stacking, respectively.

Horizontal Stacking

Otherwise known as interpolicy stacking, horizontal stacking lets you combine uninsured motorist (UM) bodily injury coverage from multiple auto insurance policies. Your name must be listed on each policy, and they must be issued by the same insurer.

For example, if you have $35,000 in UM coverage on your own policy and you're also listed on a parent’s policy with $25,000 in coverage, you could stack those for a total of $60,000 in protection against an uninsured driver.

Vertical Stacking

Also known as intrapolicy stacking, this method lets you combine uninsured motorist (UM) bodily injury coverage across multiple vehicles insured under the same policy.

For example, if you have two cars on the same policy and each has $15,000 in UM coverage, stacking them gives you a total of $30,000 in protection if you're hit by an uninsured driver. Vertical stacking only works if you insure more than one vehicle under the same policy, so it’s ideal for multi-car households looking to increase their coverage.

Stacking Insurance: State Limits

Insurance stacking isn’t available in every state. According to Allstate, 22 states allow vertical and horizontal stacking, 10 states only allow vertical stacking and 18 states prohibit stacking. 

You can review the table below to see which type of stacking is allowed in your state.

State
Vertical Stacking
Horizontal Stacking

Alabama

Alaska

Arizona

Arkansas

California

Even if your state allows stacking coverage, your insurer may not. Some states also have specific limits in place for stacking, so speak to your provider directly to explore your options for coverage.

Is Stacked Insurance Worth It?

Whether stacked insurance is worth the extra cost depends on your situation. It can offer significant benefits for drivers with multiple vehicles, those living in high-risk states or anyone who wants more protection for a small increase in premium. Below are common scenarios where stacking may be a smart move.

    car icon

    You Own Multiple Vehicles

    If you have two or more cars on the same policy, stacking lets you combine their uninsured motorist limits. This means you get more coverage if you're injured by an uninsured driver.

    carInsurance icon

     You’re Listed on Multiple Policies

    Stacking is useful when your name appears on more than one auto insurance policy from the same insurer. You can pool coverage from both policies to increase your protection.

    accident2 icon

    You Live in a High-Risk State

    States like Mississippi and Michigan have high rates of uninsured drivers. Stacked coverage gives you stronger financial backup if you're hit by someone without insurance.

    insurance2 icon

    You Want Extra Protection for Little Cost

    Stacked insurance usually adds just a few dollars to your monthly premium. That small cost could mean thousands more in coverage after a serious accident.

    female icon

    You Regularly Drive with Family or Dependents

    If multiple people in your household use your cars, stacking helps ensure better coverage for anyone injured in a crash. It’s a smart way to extend protection across your household.

Unstacked Car Insurance: What Is It?

Unstacked car insurance limits your uninsured motorist coverage to just one vehicle: the one involved in the accident. You can’t combine coverage across multiple vehicles or policies, even if you own more than one. It’s typically cheaper than stacked insurance but provides less financial protection if an uninsured driver hits you.

Not every state allows you to stack coverage. Below is a list of states that don’t allow stacking at all.

  • Alaska
  • Arizona
  • California
  • Connecticut
  • Idaho
  • Illinois
  • Iowa
  • Kansas
  • Louisiana
  • Maine
  • Maryland
  • Massachusetts
  • Michigan
  • Minnesota
  • Nebraska
  • North Dakota
  • South Dakota
  • Washington

What to Do If You Can’t Stack Insurance

If your state doesn’t allow stacked insurance, you’re not out of options. There are other ways to strengthen your financial protection in case you’re hit by an uninsured or underinsured driver.

  1. 1

    Increase Your Uninsured Motorist Limits

    If stacking isn’t allowed, you can still raise your uninsured and underinsured motorist (UM/UIM) limits for stronger protection. This gives you a higher payout if you're injured by a driver with little or no insurance.

  2. 2

    Add Medical Payments Coverage (MedPay)

    MedPay helps cover medical bills for you and your passengers, regardless of who’s at fault. It’s a good supplement if you can’t increase liability through stacking.

  3. 3

    Consider Personal Injury Protection (PIP)

    In no-fault states, PIP can help cover medical costs, lost wages and more after an accident. It provides broad coverage without depending on the other driver’s insurance.

  4. 4

    Look Into Umbrella Insurance

    An umbrella policy adds extra liability protection on top of your existing auto insurance. While it doesn’t replace UM coverage, it can protect your finances in major accidents involving lawsuits.

  5. 5

    Choose a Carrier With Strong UM Coverage Options

    Not all insurers offer the same uninsured motorist limits or flexibility. Shop around for one that offers high-limit UM coverage even without stacking.

Compare Auto Insurance Rates

Ensure you're getting the best rate for your auto insurance. Compare quotes from the top insurance companies.

Why do we need ZIP code?

Stacked vs. Unstacked Auto Insurance: Bottom Line

Stacked insurance increases uninsured motorist coverage by combining limits across vehicles or policies. It is a valuable option for multi-car owners or if you live in a state with a high number of uninsured drivers. However, it comes with slightly higher premiums. If you’re in a low-risk state or only insure one vehicle, unstacked coverage usually provides adequate protection at a lower price.

The choice between stacked and unstacked insurance depends on your location, coverage needs and budget.

Insurance Stacking: FAQ

Stacked insurance can help protect you in the event of an accident. We answer some frequently asked questions about insurance stacking.

Is stacked insurance worth it?

Is it better to have stacked or unstacked insurance?

Do I need stacked auto insurance if I have one car?

What car insurance coverage types am I allowed to stack?

Stacked Insurance Providers: Our Review Methodology

Why Trust MoneyGeek? As a trustworthy and credible source, MoneyGeek offers its readers the most recent information possible to help them acquire the necessary knowledge to make an informed decision about insurance coverage.

Not only is MoneyGeek a reliable source for information on stacked vs. unstacked insurance, but it is also reputable for information regarding auto insurance in general. Our editorial team conducts a thorough fact-check on these sources (generally government, academic, research or non-profit organizations) before citing them at the bottom of each page and/or referencing them in the text itself. When published, all references are current, verified and easily accessible.

For those who have never purchased auto insurance before, the complexity of stacked vs. unstacked insurance may be exacerbated by the subject's breadth. MoneyGeek has a team of expert writers, researchers, editors and fact-checkers to ensure readers receive easily comprehensible and accurate content. Our writers and editors come from a wide variety of professional and academic backgrounds, and their combined knowledge and experience span many topics related to insurance and finance. MoneyGeek's editorial content is supported by the findings of notable researchers in the field of behavioral economics and experimental psychology.

When you visit a page on MoneyGeek, all of the information you find there has been reviewed by a team of experts to confirm its accuracy. The methodologies employed in the content and the overall message on many MoneyGeek pages are validated and verified by subject matter experts, including research analysts, mortgage originators and insurance agents. In tandem, these experts provide transparent and reliable information on each web page so that our readers have the most accurate and valuable information.

Each MoneyGeek article is also subject to various stages of our editorial process and policy, which include research, writing, editing and fact-checking and publication. A thorough review procedure ensures we maintain high editorial standards in every published article. We research topics and frequently asked questions, design and publish content as well as offer informative, trustworthy and unbiased financial advice.

Stacked Car Insurance: Related Articles

About Mark Fitzpatrick


Mark Fitzpatrick headshot

Mark Fitzpatrick, a Licensed Property and Casualty Insurance Producer, is MoneyGeek's resident Personal Finance Expert. With over five years of experience analyzing the insurance market, he conducts original research and creates tailored content for all types of buyers. His insights have been featured in publications like CNBC, NBC News and Mashable.

Fitzpatrick holds a master’s degree in economics and international relations from Johns Hopkins University and a bachelor’s degree from Boston College. He's also a five-time Jeopardy champion!

Passionate about economics and insurance, he aims to promote transparency in financial topics and empower others to make confident money decisions.


sources
Copyright © 2025 MoneyGeek.com. All Rights Reserved