⚠️ Insurance Coverage Gap Calculator

Compare your current homeowners dwelling coverage limit against your estimated rebuild cost to see whether you have a coverage gap.

Estimated Rebuild Cost ($)

Current Dwelling Coverage ($)

Two numbers, one subtraction

Your dwelling limit is compared with what rebuilding would cost, and the shortfall is reported either way round:

gap      = max(0, rebuild cost − dwelling coverage)
surplus  = max(0, dwelling coverage − rebuild cost)
coverage = dwelling coverage / rebuild cost × 100

The starting figures, a $350,000 rebuild against $300,000 of coverage, report a $50,000 gap at 85.7% covered. Equal values report an exact match, and anything above shows the surplus rather than calling it waste.

Reading the percentage honestly

85.7% sounds close. In a total loss it is not: the policy pays its limit, and the last $50,000 of the rebuild is yours to find at the worst possible moment. The percentage matters for a different reason — policies commonly expect the dwelling limit to sit at or above 80% of replacement cost before a partial loss is settled in full, and dropping under that line can cut a kitchen fire payout as well as a total one.

Get the rebuild figure from a contractor or your insurer’s estimate, not from the sale price or the tax assessment.
Re-run it after a renovation. An extension or a new kitchen raises the rebuild cost the day it is finished.
Build in a margin. Material and labor costs move between renewals, which is what inflation guard and extended replacement cost endorsements exist to absorb.

This compares the dwelling limit only. Personal property, other structures and loss of use carry their own limits, and a house that is insured to the penny can still leave you short on contents.

Frequently asked questions

What happens if my house is underinsured?

You receive the policy limit and pay the rest. On the default figures that is $300,000 toward a $350,000 rebuild, leaving $50,000 to fund yourself.

Is being over the rebuild cost a waste of premium?

A modest surplus is cheap insurance against construction cost rises. A large one is not, because no insurer pays more than it costs to rebuild — you cannot profit from a claim by buying a bigger limit.

How do I fix a coverage gap?

Ask your insurer to raise the dwelling limit, and ask what an extended replacement cost endorsement adds. It is normally a small premium change compared with the shortfall it removes.