Your Mileage Log Burned in the Fire

Published: August 11, 2026 · Reading time: 13 min

TL;DR: The corpus is right that the Cohan rule stops at §274(d) — for vehicle, travel, meals, and gifts, no log plus no receipt normally means no deduction. That rule is about a receipt you misplaced. It is not the rule when a casualty destroyed records you actually kept. Treas. Reg. §1.274-5T(c)(5) says that where a taxpayer establishes that the failure to produce adequate records is due to loss "through circumstances beyond the taxpayer's control, such as destruction by fire, flood, earthquake, or other casualty," the taxpayer "shall have a right to substantiate a deduction by reasonable reconstruction." That is an entitlement in the regulation, not a court's discretion like Cohan and not the different provision at (c)(4). It needs no federal disaster declaration. And it buys less than people hope: it changes the evidence, never the elements, it does nothing for records you never made, and you carry the burden of proving the casualty. In the worked example below it preserves $5,096.20 of otherwise-dead §274(d) deductions — about $1,762 in tax.

Two posts on this site tell you, correctly, that there is no fallback for a lost mileage log. The Cohan rule guide puts it as "no log + no receipt = no deduction, no estimate, no Cohan." The mileage reconstruction guide says with no evidence the deduction "can be disallowed entirely."

Both are describing the same taxpayer: someone who didn't keep the record, or kept it and lost track of it in the ordinary way.

There is a third taxpayer, and the rules treat her completely differently. She kept the log. It was in the drawer of a desk that is now at the bottom of a skip, along with the receipt folder, because the upstairs unit's water heater let go in August. Nothing about her failure to produce records is her own making, and the substantiation regulations say so in one sentence that almost nobody quotes.

Three situations that look alike and are not

The single most common mistake here is treating all missing records as one problem. They are three, and only the middle row has an affirmative rule behind it.

Notice what moves between rows two and three. It is not how much documentation survives — it may be identical. It is whether records existed and what caused them to be gone. The regulation is triggered by loss, and loss presupposes possession.

What the regulation actually says

Here is the whole of it, verbatim, from 26 CFR §1.274-5T(c)(5), headed "Loss of records due to circumstances beyond control of the taxpayer":

"Where the taxpayer establishes that the failure to produce adequate records is due to the loss of such records through circumstances beyond the taxpayer's control, such as destruction by fire, flood, earthquake, or other casualty, the taxpayer shall have a right to substantiate a deduction by reasonable reconstruction of his expenditures or use."

One sentence. Four things in it are doing work:

• "Where the taxpayer establishes" — the burden is yours, and it is a burden about the event, not about the expenses
• "the loss of such records" — records that existed and are now gone
• "circumstances beyond the taxpayer's control, such as destruction by fire, flood, earthquake, or other casualty" — the operative test is the control clause; the casualties are examples of it
• "shall have a right to substantiate a deduction by reasonable reconstruction" — mandatory, addressed to the person applying the rules

One citation housekeeping note

The "T" is still correct, and it is worth a sentence because it looks like a typo for a fifty-year-old temporary regulation. The final regulation at §1.274-5 lists paragraphs (c)(3) through (c)(7) as [Reserved] and cross-references them to §1.274-5T. The reconstruction right has never been moved into the final text. §1.274-5T(c)(5) is the live citation, not a superseded one, and citing it as "§1.274-5(c)(5)" points at a reserved paragraph containing nothing.

Publication 463's recordkeeping chapter carries the rule in plain language too, under What if I Have Incomplete Records?, where the subsections run Sampling, Exceptional circumstances, and Destroyed records — the same three-way split the regulation makes.

"A right," not a court's mercy

This is the thesis, and it survives contact with the actual texts.

Cohan is discretion. Cohan v. Commissioner, 39 F.2d 540 (2d Cir. 1930) tells a tribunal it "should make as close an approximation as it can, bearing heavily if it chooses upon the taxpayer whose inexactitude is of his own making." Every clause is permissive and the doubt runs against you. It is also a doctrine the substantiation rules explicitly displaced for these categories: §274(d) "contemplates that no deduction or credit shall be allowed a taxpayer on the basis of such approximations or unsupported testimony of the taxpayer," and the regulations say in terms that this supersedes Cohan.

(c)(5) is an entitlement. "The taxpayer shall have a right." It lives inside the same strict-substantiation regulation that killed Cohan for vehicles and meals, which is exactly why it works there — it is not an outside doctrine trying to get in, it is a carve-out the regulation wrote for itself.

The practical consequence is about posture, not about winning. In a Cohan argument you are asking to be believed. Under (c)(5) you are asserting a right, and the conversation moves to whether your reconstruction is reasonable — a much better argument to be having, and one where the work you did is the evidence.

The provision next door does something different

Paragraph (c)(4) is headed "Substantiation in exceptional circumstances," and it is not the same rule. Reading them as one is the error this section exists to prevent:

"If a taxpayer establishes that, by reason of the inherent nature of the situation— (i) He was unable to obtain evidence with respect to an element of the expenditure or use which conforms fully to the 'adequate records' requirements of paragraph (c)(2) of this section, (ii) He is unable to obtain evidence with respect to such element which conforms fully to the 'other sufficient evidence' requirements of paragraph (c)(3) of this section, and (iii) He has presented other evidence, with respect to such element, which possesses the highest degree of probative value possible under the circumstances, such other evidence shall be considered to satisfy the substantiation requirements of section 274(d) and this paragraph."

A fire is not "the inherent nature of the situation." Reach for (c)(5); mention (c)(4) only if the facts genuinely fit it.

What (c)(5) does not buy you

A rule with an exception in your favour is the highest-risk thing to write about, so here is the list of what the sentence does not say. Each of these is a real way the claim falls apart.

It does not lower the elements. §274(d) requires substantiation of "(A) the amount of such expense or other item, (B) the time and place of the travel or the date and description of the gift, (C) the business purpose of the expense or other item, and (D) the business relationship to the taxpayer of the person receiving the benefit." (c)(5) changes which evidence you may use. It changes nothing about which elements you must reach. A reconstruction that produces dollar totals with no business purpose has reconstructed the easy half.

It does not apply to records you never created. "The loss of such records" presupposes records. If you never kept a mileage log, the fire destroyed nothing, and you are back in the ordinary reconstruction problem with §274(d) unrelaxed. This is the single most important qualification in the post, and it is the one people will most want to ignore.

It does not shift the burden. "Where the taxpayer establishes." You prove the casualty happened, you prove it destroyed the records, and you produce the reconstruction. An unevidenced assertion that there was a flood establishes nothing.

It is not self-executing. A right to substantiate by reasonable reconstruction is worth precisely as much as the reconstruction you actually build. Turning up with the insurance claim and no rebuilt log is the same outcome as turning up with nothing.

It is not Cohan by another name. No round numbers, no "I drove about 8,000 miles." Every audit red flag from the mileage reconstruction guide applies with full force — identical formatting, suspiciously round entries, gaps that contradict known work, and totals that exceed the odometer will sink a (c)(5) reconstruction exactly as fast as any other.

Where "beyond your control" stops

The regulation's examples are casualties. Its test is control. Those two together are what decide the hard cases, and pretending otherwise helps nobody.

Ask one question of your own facts: could ordinary care have prevented this? The more honestly the answer is yes, the less the regulation does — and because Cohan is unavailable for §274(d) items, a weak (c)(5) claim has nothing beneath it to break the fall. That is the real argument for an off-site backup rather than for a better story.

Worked example: Maya's flooded storage unit

Maya is a freelance commercial photographer. Her home office and the storage unit next door were flooded on August 15, 2026 when a supply line failed overnight in the unit above. The county was never declared a disaster area, which turns out not to matter.

Destroyed: the bound mileage logbook covering January 1 to August 14, the paper receipt folder for the same period (parking, meals, hotel folios, printed itineraries), and two prior years of receipt files.

Step 1 — she establishes the casualty. Plumber's invoice naming the failed line and the date, building management's incident email, an insurance claim (later partially denied — the denial letter is kept), and forty photographs of the unit taken before anything was moved. This file is also what supports the Form 4684 casualty loss on the destroyed equipment itself, which is a separate deduction with separate rules.

Step 2 — she establishes that records existed. The 2025 logbook, which happened to be at her accountant's, is the same format and the same handwriting. Two of the flood photographs show the open desk drawer with the current logbook in it. Her accountant's email from April refers to "the 2026 log so far."

Step 3 — she rebuilds from what the water never reached. Bank and card statements, her booking calendar, client invoices with shoot addresses, mapping software for distances, camera-roll photos including an odometer shot on January 2, and an oil-change invoice from July 6 showing the odometer again.

The mileage, at the correct two-period 2026 rates

2026 has two business mileage rates — $0.725 per mile for January 1 through June 30 (Notice 2026-10) and $0.76 per mile from July 1 through December 31 (Announcement 2026-11). Because Maya's destroyed period straddles June 30, the split is not a footnote; it is the calculation. See the 2026 mileage rate guide.

The reconstructed portion — the part that only exists because of (c)(5) — is 5,420 miles and $3,972.90 ($3,030.50 + $942.40).

It closes against the odometer. January 2 photo: 41,260. December 31: 55,910. Total miles driven 14,650, so business use is 7,930 ÷ 14,650 = 54.1%. A reconstruction that produced more business miles than the car was driven would be worthless, and the odometer anchors are what let her prove it doesn't.

And the split rate matters in dollars. Pricing all 7,930 miles at $0.725 gives $5,749.25 — $131.25 less than the correct $5,880.50, which is exactly the 3,750 miles driven after July 1 multiplied by the 3.5-cent increase. Reconstructing carefully and then applying a stale single rate throws away part of what the reconstruction recovered.

The travel and meals, rebuilt element by element

Amounts are the easy part. §274(d) wants time, place, business purpose, and — for meals — business relationship.

Travel is deductible in full: $412.00 + $624.00 = $1,036.00 on Line 24a. Meals are 50% deductible on Line 24b: $118.40 + $56.20 = $174.60, half of which is $87.30.

Maya also had three restaurant charges she could not tie to any client, meeting, or project. She dropped them. That is not timidity — an itemised reconstruction that visibly abandons what it cannot support is the reason an examiner believes the rest of it.

What the reconstruction is worth

Every dollar of that sits in a category where, on the ordinary rule, missing records mean zero. At the combined marginal rate most posts on this site use for a Schedule C filer in the 22% bracket — 15.3% self-employment tax on 92.35% of net earnings, plus 22% income tax on what is left after the deductible half of that — 34.5753%, that is about $1,762 in tax.

Worth noting how that differs from the casualty loss on the destroyed gear: that deduction lands on Form 4684 and reduces income tax only. This one reduces Schedule C net profit, so it cuts self-employment tax too.

The reconstruction memo

Nothing in (c)(5) requires one. Write it anyway. It is the difference between a spreadsheet and a substantiated reconstruction, and you will not remember any of this in three years.

One to two pages, dated and signed:

1. The event — what happened, when, with the claim number and report references
2. What was destroyed — each record type, the period covered, the physical form, where it was kept
3. How you know it existed — the prior-year log, the photograph, the email
4. Your sources — every export, statement, and account history you used, listed
5. Your method, per figure — "business miles derived from calendar entries cross-checked to client invoices; distances from Google Maps between the addresses on each invoice; totals bracketed by odometer readings of 41,260 on 2026-01-02 and 55,910 on 2026-12-31"
6. What you excluded, and why — the three untraceable restaurant charges belong here
7. The date you did the work

Then store the memo, the casualty file, and the source exports together, off-site and backed up. Losing the reconstruction to the next incident is a genuinely avoidable indignity.

Three things that come up afterwards

Prior years are covered too. A fire in 2026 destroys the 2023–2025 files sitting in the same cabinet, and those years are still inside the retention window. (c)(5) applies to them on the same terms if an examination ever reaches back — which is another reason the destroyed-records inventory should list every period, not just the current one.

No federal declaration is needed. The regulation does not mention one. A declaration matters for filing postponements under §7508A and for the §165(i) prior-year loss election, but it is not a precondition to reconstructing your substantiation. Maya's county was never declared anything.

The IRS publishes its own reconstruction playbook. Its disaster-records guidance points to tax transcripts through Get Transcript or Form 4506-T — write the disaster designation in red on a mailed request to expedite it and waive the fee — plus bank and credit card statement retrieval, phone photographs taken before the event, supplier invoices going back a year, contractor statements, county assessor records, and the room-by-room workbook in Publication 584-B for business property. Most of that is aimed at valuing the destroyed property rather than at §274(d) substantiation, but the sources overlap almost completely, and using the list the IRS itself published is a reasonable definition of reasonable.

The habit that makes all of this moot

(c)(5) is a genuine right and it is still a bad day. Maya spent a weekend rebuilding a record she had already built once, and she recovered a defensible number rather than a certain one.

The version of this story where nothing happens is the one where the log and the receipts were never in the drawer to begin with — captured at the point of sale, synced off-site, and untouchable by anything that happens to a building. That is the 3-2-1 rule applied to receipts, and the off-site copy is the leg a shoebox can never have.

One more thing worth doing this week, for a different reason: photograph your workspace once a year. It takes ninety seconds and it timestamps itself. After a flood it is how you establish that the logbook was in the drawer.

Frequently Asked Questions

A fire destroyed my mileage log. Can I still claim the mileage?

Yes, if you can establish that the records existed and that a casualty destroyed them. Treasury Regulation §1.274-5T(c)(5) says that where a taxpayer establishes that the failure to produce adequate records is due to the loss of those records through circumstances beyond the taxpayer's control, such as destruction by fire, flood, earthquake, or other casualty, the taxpayer shall have a right to substantiate a deduction by reasonable reconstruction of his expenditures or use. That provision is the reason vehicle, travel, and meal deductions are not automatically gone after a disaster, even though those categories fall under §274(d) where the Cohan rule was expressly superseded. Two conditions carry the whole thing. You have to establish the casualty, which is what the insurance claim, fire or police report, and dated photographs are for. And you have to establish that adequate records existed to be destroyed, because the regulation is triggered by the loss of records, not by their absence.

How is §1.274-5T(c)(5) different from the Cohan rule?

The difference is who is doing what, and it is not a technicality. Cohan v. Commissioner, 39 F.2d 540 (2d Cir. 1930) is a rule of judicial discretion: Judge Learned Hand said a court should make as close an approximation as it can, bearing heavily if it chooses upon the taxpayer whose inexactitude is of his own making. A court may estimate; it is not obliged to, and it is invited to resolve doubt against you. Congress then enacted §274(d) and the regulations state that §274(d) contemplates that no deduction shall be allowed on the basis of approximations or unsupported testimony, expressly superseding Cohan for travel, meals, gifts, and listed property. Paragraph (c)(5) sits inside those same strict-substantiation regulations and uses mandatory language pointed the other way: the taxpayer shall have a right to substantiate by reasonable reconstruction. It is not a court's mercy that you hope for after the fact. It is an entitlement written into the substantiation rules themselves, which an examiner is applying rather than granting. What it is not is a licence to estimate — the reconstruction still has to establish each element of each expenditure from real sources.

Does the exception cover a stolen laptop or a phone I left in a taxi?

Those two sit on opposite sides of the line and it is worth being honest about it. The regulation's operative test is circumstances beyond the taxpayer's control, and its enumerated examples are all casualties: destruction by fire, flood, earthquake, or other casualty. A burglary of your office in which the filing cabinet and the laptop were taken is a strong claim on the operative words even though theft is not in the example list, because a documented crime with a police report is the paradigm of something outside your control. A phone left in a taxi is a much weaker claim, because the proximate cause was your own carelessness, and it is exactly the inexactitude of his own making that Cohan bore heavily against — except that for a §274(d) expense Cohan is unavailable, so a weak (c)(5) claim has nothing underneath it to fall back on. The practical test to apply to your own facts: could you have prevented this by being more careful? The more honestly the answer is yes, the less the regulation helps, and the more the real answer is an off-site backup you should already have had.

What does a 'reasonable reconstruction' actually have to contain?

Everything §274(d) required in the first place, sourced differently. The statute requires you to substantiate the amount, the time and place of travel or the date and description of a gift, the business purpose, and the business relationship of the person receiving the benefit. Paragraph (c)(5) changes the evidence you may use, not the elements you must establish, so a reconstruction that produces dollar totals and no business purpose has not reconstructed anything. In practice that means bank and card statements for amounts and dates, calendar or CRM entries and client invoices for purpose and place, mapping software for distances between addresses you can prove you visited, odometer readings from oil-change and inspection records to bracket the annual total, duplicate receipts from merchants who retain transaction history, and photographs already sitting in your phone's camera roll. The IRS's own disaster-records guidance points to the same sources, plus tax transcripts via Get Transcript or Form 4506-T and supplier invoices going back a year. Then write down the method you used, so the reconstruction is auditable rather than merely asserted.

Do I need a federally declared disaster for the reconstruction right to apply?

No. Nothing in §1.274-5T(c)(5) mentions a federal declaration, a disaster area, or FEMA. The test is whether records were lost through circumstances beyond the taxpayer's control, and a burst supply line that floods one storage unit at three in the morning satisfies it exactly as a hurricane would. This mirrors the position on the casualty loss deduction for the destroyed property itself, where the federally declared disaster limitation lives in §165(h) and reaches only personal-use property while business property is governed by §165(c)(1) and was never restricted. A federal declaration does matter for other things — filing and payment postponements under §7508A, and the §165(i) election to claim a disaster loss on the prior year's return — but it is not a precondition for reconstructing your substantiation. Do not let the absence of a declaration talk you out of the deduction.

Authoritative References

• 26 CFR §1.274-5T — Substantiation requirements (temporary): (c)(4) exceptional circumstances, (c)(5) loss of records
• 26 CFR §1.274-5 — Substantiation requirements (paragraphs (c)(3)–(7) reserved, cross-referenced to §1.274-5T)
• IRC §274(d) — Substantiation required
• IRS — Reconstructing records after a natural disaster or casualty loss
• IRS — Publication 463, Travel, Gift, and Car Expenses (ch. 5, "What if I Have Incomplete Records?")
• IRS — About Publication 584-B, Business Casualty, Disaster, and Theft Loss Workbook
• IRS — Publication 547, Casualties, Disasters, and Thefts
• IRS — Standard Mileage Rates
• Cohan v. Commissioner, 39 F.2d 540 (2d Cir. 1930)

Related reading: The Cohan rule and lost receipts · How to reconstruct a mileage log after the fact · Casualty and theft losses on business property · Backing up business receipts to the cloud · The 2026 IRS mileage rate · Contemporaneous mileage log requirements

The Right to Reconstruct Is Better Than Needing It

Paragraph (c)(5) is a real entitlement and it is worth knowing you have it. It is also a weekend of forensic work to recover a number you had already earned once. The version where the flood takes the desk and not the deduction is the one where the log and the receipts were never only in the drawer — captured on your phone, extracted, categorized to the right Schedule C line, and stored off-site the moment they were created. CentSense logs each business trip at the correct 2026 rate for the date you drove it and keeps every scanned receipt in the cloud, so a reconstruction is something you read out of an export rather than rebuild from wreckage. Free tier includes 10 AI scans per month; Solo is $5/month for unlimited scanning and mileage logging.

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This guide is general education for U.S. freelancers and Schedule C filers in 2026. It is not personalized tax advice. Whether a particular loss was "beyond the taxpayer's control" and whether a given reconstruction is "reasonable" are fact-specific determinations, and a casualty that destroys business records usually raises a Form 4684 loss on the destroyed property at the same time. Take both to a CPA or EA before filing.