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Casualty Loss Deduction Calculator

Calculate your deductible casualty loss from a federally declared disaster, after applicable floors.

Result

Deductible Casualty Loss
$20,900.00

Since 2018, personal casualty losses are deductible only if attributable to a federally declared disaster. Applies a $100 per-event floor, then a further reduction of 10% of AGI - two smaller floors that together mean only substantial, uninsured disaster losses typically qualify for any deduction.

About the Casualty Loss Deduction

This calculator figures out how much of a property loss from a federally declared disaster remains deductible after insurance reimbursement and the two floors the IRS applies to personal casualty losses. Since 2018, only losses tied to a federally declared disaster qualify at all, so the tool is aimed at taxpayers who have been through a disaster-related loss and want to know what portion, if any, survives the floors. It's built for itemizers assessing a real property loss, not routine accidents or theft.

How It Works

Enter the drop in the property's fair market value from the casualty event, any insurance reimbursement received, and your adjusted gross income. The calculator subtracts insurance proceeds from the loss first, applies a flat $100 per-event floor, and then subtracts 10% of your AGI from what remains. Whatever is left after both reductions is the deductible casualty loss; if either subtraction exceeds the remaining balance, the deduction is zero.

Loss After Insurance = max(Property Loss - Insurance Reimbursement, 0). Loss After Per-Event Floor = max(Loss After Insurance - $100, 0). Deductible Loss = max(Loss After Per-Event Floor - (AGI x 10%), 0).

Formula & Methodology

For a hand calculation, start with the drop in fair market value caused by the disaster and subtract any insurance money received for that specific loss to find the unreimbursed amount. From that, subtract $100 as the flat per-casualty-event floor. Then calculate 10% of your adjusted gross income and subtract that from what remains. Anything left after both subtractions is deductible, and if either step produces a negative number, the running total stops at zero rather than going below it.

Examples

Partially Insured Flood Damage

Property value dropped $60,000, insurance paid $30,000, AGI is $90,000. Loss after insurance is $30,000, minus the $100 floor is $29,900, minus 10% of AGI ($9,000) leaves a $20,900 deductible loss.

Small Uninsured Loss, Higher Income

Property value dropped $8,000 with no insurance reimbursement, AGI is $150,000. Loss after insurance is $8,000, minus $100 is $7,900, but 10% of AGI ($15,000) exceeds that remaining amount, so the deductible loss is $0.

Advantages

  • Applies both required floors in the correct order, so users don't have to manually chain the per-event and AGI-based reductions themselves.
  • Makes clear how much insurance reimbursement, not just the raw property damage figure, changes the deductible outcome.
  • Shows immediately when a loss is too small relative to AGI to produce any deduction, before attempting to itemize.

Common Mistakes

  • Using the original purchase price or replacement cost instead of the actual decrease in fair market value caused by the casualty.
  • Forgetting to subtract insurance reimbursement before applying the floors, which overstates the deductible loss.
  • Assuming any personal casualty loss qualifies, when current law limits the deduction to losses connected to a federally declared disaster.

Edge Cases to Watch For

  • If insurance reimbursement equals or exceeds the property loss, the deductible amount is zero before either floor is even applied, since a fully insured loss isn't an out-of-pocket loss.
  • The two floors stack in order: the flat $100 per-event floor is subtracted first, then 10% of AGI is subtracted from what remains, so a higher-income taxpayer needs a genuinely large uninsured loss before any deduction survives.
  • The calculator assumes the loss qualifies as connected to a federally declared disaster; ordinary theft, accidents, or losses outside a declared disaster area generally aren't deductible under current law regardless of what this tool computes.

Common Use Cases

  • Homeowners in a federally declared disaster area estimating their itemized deduction after insurance settles.
  • Tax preparers checking the floor calculations for a client's disaster-related property loss.
  • Taxpayers deciding whether a casualty loss is large enough relative to their AGI to make itemizing worthwhile that year.
Written & fact-checked by the Calculateus TeamLast updated August 5, 2026How we verify our formulas

Frequently asked questions

Why was the casualty loss deduction restricted to federally declared disasters?

The Tax Cuts and Jobs Act narrowed this deduction (previously available for any qualifying casualty, like an isolated house fire or theft) specifically to losses connected to federally declared disasters, as part of broader efforts to simplify the tax code and reduce itemized deductions - this means routine personal losses like a random accident or theft generally no longer qualify unless they occur within a federally declared disaster area.

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Conclusion

Because the deduction is reduced by both a flat $100 floor and 10% of AGI, only substantial, largely uninsured disaster losses typically produce a meaningful deduction. This calculator shows exactly where a specific loss lands after both reductions, under the current rules limiting the deduction to federally declared disasters.

References