Flood vs Standard Coverage Gap Calculator
Estimate the financial gap between what your standard homeowners policy covers and what a separate flood insurance policy would cover in a flood event.
Formulas Used
Building Loss = Home Replacement Value × (Flood Damage % ÷ 100)
Contents Loss = Contents Value × (Contents Damage % ÷ 100)
Total Loss = Building Loss + Contents Loss
Standard Policy Payout = max(0, (Building Loss + Contents Loss) × Standard Flood Cover % − Standard Deductible)
Flood Policy Building Payout = max(0, min(Building Loss, NFIP Building Limit) − Flood Deductible)
Flood Policy Contents Payout = max(0, min(Contents Loss, NFIP Contents Limit))
Out-of-Pocket Without Flood Policy = max(0, Total Loss − Standard Payout)
Out-of-Pocket With Flood Policy = max(0, Total Loss − Flood Total Payout)
Net Benefit of Flood Policy = Out-of-Pocket Without − Out-of-Pocket With
Above-Limit Gap = max(0, Building Loss − NFIP Building Limit) + max(0, Contents Loss − NFIP Contents Limit)
Assumptions & References
- Standard homeowners (HO-3) policies do not cover flood damage; the "Standard Flood Cover %" input defaults to 0% and reflects rare endorsements only.
- NFIP (National Flood Insurance Program) maximum limits are $250,000 for building and $100,000 for contents as of 2024 (FEMA).
- Per NFIP rules, the building deductible is applied to the building coverage first; contents coverage has a separate deductible (simplified here as $0 for contents).
- Private flood insurance may offer higher limits and broader coverage than NFIP.
- Damage percentages are user estimates; actual loss depends on flood depth, construction type, and FEMA flood zone.
- This calculator does not account for Additional Living Expenses (ALE), which NFIP does not cover but some private policies do.
- References: FEMA NFIP Flood Insurance Manual (2024); III (Insurance Information Institute) — Flood Insurance fact sheet.