Free · No email · Updated 2026
Am I underinsured on my home?
5 inputs, 30 seconds. Get your real reconstruction cost — what a builder will charge to rebuild your house from foundation up post-loss — and compare it to your current dwelling coverage limit. 4-tier verdict tells you whether to call your carrier this week or not.
Dangerously underinsured
Coverage is below 75% of reconstruction. You will lose your home AND a large chunk of equity in a total loss. Coinsurance penalty is likely active even on partial claims. Increase coverage immediately — this is the single highest-ROI policy change you can make.
Reconstruction breakdown
Next step
Now check: if a roof claim hits, will it actually pay out? →
Your dwelling coverage feeds into the roof claim payout math. Run the ACV / RCV / hailbelt-deductible numbers using the $300,000 number you just entered.
Worst case: total loss
Run a $122,625 HEL → see monthly payment to bridge a total-loss gap
Most homeowners can't write a $122,625 check in 90 days. A HEL is the post-loss bridge product — but the better fix is raising Coverage A NOW so you never need it.
Underinsurance is the single most common (and most expensive) homeowners insurance mistake. Most Americans insure their home for whatever the carrier's automated estimator spit out at closing — which is often based on a 5-year-old construction-cost index. After 24-38% labor and materials surge in 2022-2024, that produces a real coverage gap on more than half of US homes. This calculator runs the same Marshall & Swift + RSMeans rebuild math your carrier should be using (but often isn't), with a 15% post-disaster surge factor priced in.
How this calculator works
- Anchor on reconstruction, not market value — Most homeowners insure for the market value of the property at purchase — but market value includes land. Insurance only pays to rebuild the structure. Coverage A (Dwelling) should match reconstruction cost, which is typically 60-80% of market value in urban areas, 90-110% in rural areas where land is cheap.
- Plug in finished square footage — Above-grade only. Basements and attached garages get captured separately via the feature toggles below — counting them in the base sqft double-counts. Pull the number from your county tax assessor's online record (usually free, accurate to within ±50 sqft).
- Pick your state's cost tier — California and New York run ~40% above the national average rebuild cost. Texas and Florida are at the base. Midwest states (Minnesota, Iowa, Indiana) run ~15% below. Hawaii, Alaska, and DC are flagged outliers — call a local builder for an actual quote if you live in one.
- Choose construction quality honestly — Builder-grade tract home = Budget. Standard 2026 single-family home with normal finishes = Mid. 9-foot ceilings + custom millwork + designer fixtures + hardwood = Premium. Overstating drives reconstruction cost up by 35% — be honest.
- Flag features that boost rebuild — Finished basement (+8%), attached 2-car garage (+5%), custom features like timber-frame beams, slate or tile roof, plaster walls, or radiant heat (+12% as a combined boost). Multiple features stack additively, not multiplicatively.
When to use this vs. skip it
Annual renewal arrives
30 seconds to verify you're still adequately insured. Catch the 18-month drift from cost inflation before it becomes a 30-50% gap.
Just finished a major renovation
Kitchen, addition, finished basement, roof upgrade, or anything over $25K should trigger a Coverage A increase. Run our numbers, call carrier, get endorsement.
Carrier raised your premium materially
Carriers often justify hikes by raising Coverage A automatically. Verify their new number isn't inflated — they sometimes round UP aggressively to justify a higher premium.
Buying a new home
Don't accept the lender's required minimum coverage. Lenders require enough to cover the mortgage — that's typically 60-80% of reconstruction. Insure for actual rebuild cost, not loan payoff.
Bought a home in a high-disaster zone
Wildfire / hurricane / hailbelt zones experience supply surges of 25-40% on rebuild quotes during regional disaster events. Use our default 15% surge factor or raise it if you're in a recently-hit zone.
Common mistakes homeowners make
- ×Using market value instead of reconstruction cost — overcounts by 20-40% in urban areas (you pay too much premium) OR undercounts in rural areas (you're underinsured).
- ×Trusting the carrier's auto-estimator without verifying their construction-cost basis year. Most are calibrated to pre-2022 data and silently under-estimate by 18-30%.
- ×Forgetting to re-run after a major renovation. A new kitchen typically adds $25-60K to reconstruction cost — and most homeowners never raise Coverage A after the project.
- ×Ignoring the 80% coinsurance clause. If you're under 80%, every claim (including a $5K kitchen fire) gets reduced proportionally. This is the silent killer of partial-loss claims.
- ×Buying Guaranteed Replacement Cost as a substitute for accurate Coverage A. The rider is great but only kicks in for total losses — partial losses still get reduced by coinsurance based on your base limit.
Last updated · Reviewed by the HavenCostGuide methodology desk
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