and AGI to see your Form 4684 deduction
IRC §165(h) · Form 4684 Section A · Schedule A Line 15 · TY 2025 & 2026
Figure your deductible personal casualty or theft loss under IRC §165(h) using IRS Form 4684 Section A. Enter your adjusted basis, fair market value before and after, insurance recovery, the type of disaster declaration, any personal casualty gains, and your AGI to see the per-casualty loss, the $100 floor, the 10 percent of AGI floor, and the amount that flows to Schedule A line 15. The tool also reflects the OBBBA state-declared-disaster expansion effective tax year 2026.
Want the full rulebook - what counts as a casualty, how the federally-declared and state-declared disaster categories interact, theft loss timing, the qualified disaster special rules, and the Form 4684 walkthrough? Read the companion guide.
Read the Casualty and Theft Loss Guide →Under IRC §165(h), an individual's personal casualty or theft loss is deductible only if the loss is attributable to a federally declared disaster. The OBBBA (P.L. 119-21) made that limitation permanent and, beginning with tax year 2026, expanded it to include state-declared disasters (Governor plus Treasury Secretary determination). The loss equals the smaller of adjusted basis or FMV decline, minus insurance recovery, minus a $100 per-casualty floor, minus 10 percent of AGI. The amount goes on Schedule A line 15 and only helps if you itemize. Qualified disaster losses use a $500 floor and skip the 10 percent of AGI floor.
| Item | Tax Year 2026 | Tax Year 2025 |
|---|---|---|
| Federally declared disaster eligible | Yes | Yes |
| State-declared disaster eligible | Yes (OBBBA §165(h)(5)(A) and (h)(5)(C)) | No (federal only) |
| Limitation permanent (no sunset) | Yes (OBBBA) | Yes (OBBBA) |
| $100 per-casualty floor | $100 (permanent, OBBBA) | $100 (permanent, OBBBA) |
| 10% of AGI floor | 10% (permanent, OBBBA) | 10% (permanent, OBBBA) |
| Qualified disaster loss floor | $500 per event (no AGI floor) | $500 per event (no AGI floor) |
| Available without itemizing | Only for qualified disaster loss (std deduction add-on) | Same |
| Personal casualty gain offset | Allowed against any personal casualty loss | Allowed against any personal casualty loss |
| Prior-year disaster election | §165(i), file with Form 4684 Section D | §165(i), file with Form 4684 Section D |
| Reporting location | Schedule A line 15 (Form 4684 Section A) | Schedule A line 15 (Form 4684 Section A) |
The One Big Beautiful Bill Act (P.L. 119-21) made the §165(h)(5) declared-disaster limitation permanent and added state-declared disasters as an eligible category for tax years beginning after December 31, 2025. The $100 and 10 percent of AGI floors are statutory and are not adjusted for inflation. Sources: IRC §165, IRS Form 4684, and the IRS "Casualty loss deduction expanded and made permanent" newsroom.
The tool walks Section A of Form 4684 in the order the IRS does. For the full rules - what counts as a casualty, how state-declared disasters work, theft loss timing, the prior-year election, and the qualified disaster special rules - see the Casualty and Theft Loss Guide.
For 2025 and after, §165(h)(5) blocks any deduction for a personal casualty or theft loss unless the loss is attributable to a federally declared disaster. OBBBA expanded this to include state-declared disasters for tax years beginning after December 31, 2025. If you have no declaration but you have personal casualty gains, the loss can offset gains but not produce an itemized deduction.
Line 2 is your adjusted basis. Line 5 is FMV immediately before the event; line 6 is FMV immediately after. Line 7 (FMV decline) is line 5 minus line 6. The casualty loss before insurance is the smaller of line 2 or line 7.
Subtract insurance proceeds, FEMA grants, employer payments, or anything else received or reasonably expected. If recovery exceeds basis, you have a casualty gain instead of a loss (and it appears on line 14 with other gains).
Reduce each per-casualty loss by $100 ($500 for qualified disaster losses). The floor is per event, not per property and not per spouse. Spouses on a joint return are treated as one individual under §165(h)(4)(B).
Personal casualty gains reduce personal casualty losses. The portion of losses offset by gains is not subject to the 10 percent of AGI floor (it is deductible in computing AGI under §165(h)(4)(A)). Surplus losses go to the AGI floor.
Only the surplus loss above 10 percent of AGI is deductible. The result flows to Schedule A line 15. Qualified disaster losses skip this floor and may be added on top of the standard deduction without itemizing.
The 2026 expansion to state-declared disasters is the most important change in years. Clients in states with active emergency management (California wildfires, Florida hurricanes, Texas freezes, Louisiana storms) routinely lost personal property in events that never reached the FEMA declaration threshold. For 2025 those losses remain non-deductible under §165(h)(5). For 2026 and after, if the Governor and the Treasury Secretary make the determination required by §165(h)(5)(C), the loss is back in play. We are already advising clients to keep documentation, photographs, and contemporaneous appraisals for in-state events while the formal Treasury determination process for state declarations beds down. Do not assume your state declaration automatically qualifies until Treasury concurs.
The lesser-of test is where DIY filers overstate losses. They calculate the FMV decline and stop, forgetting that the deduction is capped at adjusted basis. For older property bought decades ago, FMV decline can dwarf basis; for newer property where you have not yet depreciated much, basis usually controls. Pulling the original purchase records, the chain of improvements, and any prior casualty deduction is the unglamorous part of the engagement that drives the right number.
The 10 percent of AGI floor swallows most claims. A $10,000 personal casualty in a household with $120,000 of AGI is a zero deduction. We use Example 4 above on the consult call to set expectations early, then use the qualified disaster loss exception (Example 3) when the event is on the statutory list. The qualified disaster loss list is narrow: most ordinary federally declared disasters do not meet that special definition. Check the FEMA DR number against the qualified disaster loss list in the Form 4684 instructions before claiming the qualified treatment.
The insurance claim requirement under §165(h)(4)(E) is the trap that destroys returns on audit. If the property was insured and the client did not file a timely claim, the insured portion is permanently nondeductible. We always ask: was the property insured? Was a claim filed? When? Was it accepted or denied? Without that paper trail, we will not include the insured portion of the loss in the return. The Form 4684 line 3 figure has to tie out to the carrier's settlement letter or denial.
Pull the FEMA DR or EM declaration number and confirm the incident period covers your loss. Run this calculator with Loss Type = Federally declared. If the loss occurred in a year you have not yet filed for, consider the prior-year election on Form 4684 Section D to get cash sooner. Read the Casualty and Theft Loss Guide for the FEMA-number lookup and election details.
For tax year 2025 the loss is still not deductible under federal law (no federal declaration). For tax year 2026 and after, the state-declared category applies once Treasury concurs. Document the loss now (photos, repair estimates, appraisals) and run the calculator with Loss Type = State-declared and Tax Year = 2026 to see your projected deduction.
Run the Itemize vs Standard Deduction Calculator with the line 15 amount added to your Schedule A total. If you do not itemize and the loss is a qualified disaster loss, you can still add it on top of the standard deduction; otherwise the deduction is lost. The Itemized Deductions List walks through every Schedule A line.
Casualty gains and losses interact differently from regular capital gains and losses. Net the per-event amounts on Form 4684 line 14 and line 15 before applying the 10 percent of AGI floor. Read the netting rules in the guide and review your AGI & MAGI Calculator to confirm the floor amount.