Car insurance glossary
What is stacking insurance coverage?
Stacking combines eligible uninsured or underinsured motorist limits from more than one vehicle or policy when the law and contract allow it.
Also called: stacked UM coverage
Glossary date: June 8, 2026
How it works
Some states permit stacking, restrict it, or allow a policy to prohibit it. The way limits combine can differ for one policy and multiple policies.
Example
Two vehicles each have a $50,000 eligible UM limit. If stacking is allowed, the available limit may be higher than either individual limit.
Why it matters
The number of insured vehicles does not automatically mean their limits can be added together.
What to check on your policy
Read the anti-stacking language, state rules, vehicle schedule, and any premium charge for stacked coverage.
Related car insurance terms
Put the terms into context
Read the full guide, find a nearby GoAuto office, or start a quote with the coverage details you want to discuss.