Calculate Home Insurance

The five steps to calculate home insurance

Calculating home insurance isn’t guesswork once you follow the right order. Each step builds on the one before it, and almost everything traces back to your home’s rebuild cost.

1. Calculate the dwelling (rebuild) cost. Multiply finished living area by a realistic local rebuild cost per square foot, then add finished basements, detached structures and an upgrade factor for custom finishes. The calculator above does exactly this. This is your Coverage A.
2. Set personal property. Take 50–70% of the dwelling figure, or do a room-by-room inventory for accuracy. This is Coverage C.
3. Set other structures and loss of use. Other structures (fences, sheds, detached garage) default to ~10% of the dwelling; loss of use (temporary living costs) to ~20%.
4. Choose liability limits. Match these to what you’d need to protect in a lawsuit — typically $300,000–$500,000, with an umbrella policy on top if your net worth is higher.
5. Pick a deductible. Higher deductible, lower cost. Choose what you could pay out of pocket today, and check whether wind/hurricane deductibles are percentage-based.

A worked example, start to finish

Take a 1,800-square-foot home with no basement in an area where rebuild cost is about $190 per square foot, owned by a household with roughly $250,000 in net worth and $90,000 of belongings.

• Dwelling (A): 1,800 × $190 = $342,000
• Personal property (C): use the inventory figure of $90,000 (about 26% of dwelling — below the 50% default, so the default would also be safe)
• Other structures (B): 10% of A = $34,200
• Loss of use (D): 20% of A = $68,400
• Liability (E): $300,000 to cover net worth
• Deductible: $1,500

Those six numbers are everything an insurer needs to quote you — and because you calculated them yourself, you can tell immediately if a quote is built on the wrong assumptions.

What home insurance does — and doesn’t — cover

A standard policy covers sudden, accidental damage from perils like fire, wind, hail, theft and many kinds of water damage from inside the home. It does not cover flood (you need a separate flood policy), earthquake (a separate endorsement or policy), normal wear and tear, or maintenance issues like mold from a long-ignored leak. Knowing these gaps is part of calculating your true coverage needs — the policy limit is only useful for the things the policy actually pays for.

Keep your calculation current

Recalculate after any renovation that adds square footage or value, and at least once a year to keep pace with construction-cost inflation. Materials and labor prices have moved sharply in recent years, and a rebuild cost that was accurate three years ago may now leave you underinsured. Ten minutes with the calculator each renewal is the cheapest insurance audit you’ll ever do — and it keeps both your protection and your cost honest.