What Is the 80% Rule in Home Insurance?
Kenneth Schaub, Owner & Licensed Insurance Advisor
The 80% rule, also called the coinsurance clause, is a provision in most standard homeowners policies that reduces your claim payout if your dwelling coverage is below 80% of your home's true rebuild cost, even for small, partial losses like a roof repair. It exists so homeowners can't deliberately under-insure and still collect a full payout on minor claims.
How does the 80% rule actually work?
If your dwelling coverage falls below 80% of your home's replacement cost at the time of a loss, your insurer pays only a proportional share of the claim, not the full repair cost. The formula insurers use is:
Payout = (Actual coverage ÷ Required coverage) × Damage amount − Deductible
What does this look like with real numbers?
Take a home with a $400,000 replacement cost. The required coverage under the 80% rule is $320,000 (80% of $400,000).
| Scenario | Dwelling coverage carried | Meets 80% rule? | Payout on a $40,000 claim |
|---|---|---|---|
| Fully insured | $400,000 | Yes | $40,000 (minus deductible) |
| At the threshold | $320,000 | Yes, exactly | $40,000 (minus deductible) |
| Under-insured | $280,000 | No (70%) | $35,000 (87.5% of claim) |
In the under-insured example, the homeowner carries $280,000 against a $320,000 requirement, only 87.5% of what's required, so even a routine partial claim pays out 87.5% of the damage amount instead of the full repair cost.
Why would someone end up under-insured without realizing it?
The most common trigger is a home renovation or addition that raises the rebuild cost without the homeowner updating their coverage limit to match. Construction costs have also risen steadily in recent years, meaning a dwelling limit set accurately three or four years ago may no longer reflect current rebuild cost today.
How do I know if I'm below the 80% threshold?
Get a current replacement-cost estimate for your home, most carriers or independent appraisers can calculate this, and compare it to your policy's dwelling coverage limit. If your limit is below 80% of that figure, raising it closes the gap before it costs you at claim time, not after.
Make sure your coverage limit actually reflects today's rebuild cost. Compare home insurance options or start a free quote in minutes.
Frequently asked questions
What is the 80% rule in homeowners insurance?
It's a coinsurance clause that reduces your claim payout, even on small claims, if your dwelling coverage is below 80% of your home's true replacement (rebuild) cost.
Does the 80% rule apply to total losses or just partial claims?
Both, but it's most often noticed on partial claims, like a roof or kitchen fire repair, since homeowners frequently don't realize they're under-insured until a routine claim pays out less than expected.
How can I avoid triggering the 80% rule?
Keep your dwelling coverage limit updated to at least 80% (ideally 100%) of your home's current replacement cost, especially after any renovation, addition, or period of rising construction costs.
Is the 80% rule based on my home's market value?
No, it's based on replacement cost, the price to rebuild the home with current labor and materials, which is a different number than market value or purchase price.
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