Guide · Mileage
What the IRS actually requires in a mileage log
Most people lose this deduction twice. First by not recording trips, and then by trying to reconstruct them in April from calendar entries and memory — which is exactly the kind of record that does not survive scrutiny.
The requirements themselves are short. It is worth reading them once properly.
The four things every trip needs
For each business trip you must be able to show:
- The date of the trip.
- The destination — where you went.
- The business purpose — why. "Client meeting — Acme" is enough; "work" is not.
- The miles driven.
On top of the per-trip record you need your total mileage for the year, because the deduction rests on the share of your driving that was for business. Without a total, a business figure means nothing on its own.
The requirement people miss is purpose. Distance and date come from a phone easily. Purpose has to come from you, and it is the field an examiner reads first.
Write it down at the time
Records are expected to be kept contemporaneously — at or near the time of the trip. A log assembled months later from memory is weaker evidence, and a log that is suspiciously round (every trip 20 miles, every week identical) invites exactly the questions you do not want.
This is the real argument for automatic tracking. Not that it saves typing, but that the record exists on the day the trip happened rather than the day you needed it.
Standard rate or actual expenses
| Method | What you track | Best when |
|---|---|---|
| Standard mileage | Business miles × the published rate — 72.5¢ before 1 July 2026, 76¢ after | Your car is inexpensive to run, or you want the simplest defensible record |
| Actual expenses | Fuel, insurance, repairs, depreciation — multiplied by your business-use percentage | The vehicle is expensive, heavily used for business, or recently bought |
You still need the mileage log either way. The actual-expense method needs the business-use percentage, and that comes from the same numbers.
How long to keep it
Three years from the date you filed is the normal period the IRS has to assess additional tax, so three years is the working answer. Six if a return understated income by more than 25%. There is no time limit where no return was filed.
Storage matters more than people expect. A log that only exists inside an app you have stopped paying for is not a record you control. Keep an export.
A note on other countries
The four elements are close to universal, but the arithmetic is not. In the UK, HMRC pays 45p a mile for the first 10,000 business miles and 25p after that. In Canada, the per-kilometre rates apply to employee reimbursement; self-employed filers must use actual expenses and business-use percentage, which requires odometer readings at the start and end of the year.
If an app quotes you a single flat rate per mile regardless of country, it is doing the US calculation wherever you live.
Where DriveSnap fits
DriveSnap records the date, distance and route of every drive automatically, and asks you for the purpose with one swipe — the field that has to come from a human. It runs entirely on your iPhone: no account, no servers, and no cap on how many drives it will log.
At year end it exports a CSV with every trip dated, categorised, rated and totalled. The rate is stamped onto each drive when it is recorded, so updating it next January never rewrites a year you have already filed.
This is general information, not tax advice, and rates change. Check the current figures with the IRS or your accountant before filing.