How to record a personal detour during a work trip

General US federal recordkeeping information, not individual tax advice. Tax treatment depends on your circumstances; consult a qualified adviser for your claim.

The IRS distinguishes business travel from personal use and discusses indirect travel between workplaces. Use that guidance with your actual facts; do not assume a map's shortest route is always the required or correct business distance.

Separate the facts from the decision

First write down where you went and the distance you actually recorded. Then identify the personal stop and the part of the journey it affected. Keep reasons for necessary route changes, such as a closure, separate from a personal errand.

A single GPS trace may cover multiple purposes. Conversely, several saved trips may make up one business task. Neither the number of app entries nor an automatic classification is the final answer about which miles belong in a claim.

A fictional out-and-back detour

Nora travels from her business workshop to a client. On the way, she leaves the established route to collect a personal parcel, then returns to the same junction before continuing. Her records support these segments:

Segment	Miles	Evidence note
Workshop to junction	5.0	Work route
Junction to parcel shop and back	4.0	Personal detour
Junction to client	7.0	Work route
Total travelled	16.0	Reconcile with original record

For this deliberately simple example, the documented work-route segments add to 12.0 miles and the personal detour is 4.0 miles. Keeping both amounts preserves the full 16.0-mile journey. This is a recordkeeping illustration, not a conclusion about a different route or a home-to-work journey.

A stop that lies directly along the route may have different facts from this out-and-back example. Do not manufacture a four-mile deduction merely because another driver's worksheet used one. Explain the actual route and ask about ambiguous treatment.

Make a correction without creating a second journey

Save the original record or export before a substantial change. In FlatMile, an unlocked drive's distance can be edited; that does not mean the app supplies a dedicated split-and-tax-allocation feature. Use supported fields and a separate worksheet where needed. Keep a note connecting the edited record to the original journey and the reason for the change.

If you add a manual record to represent an omitted segment, check that it is not also included in the existing trip total. Do not keep a full 16-mile business record and add a separate 12-mile business record for the same travel. That would inflate the log rather than clarify it.

Reconcile the day before exporting

Add business, personal and unresolved distances and compare the result with the day's original recorded travel. Review purposes and vehicle assignments as well as arithmetic. A correct subtotal attached to the wrong journey still misleads a reviewer.

Keep the route worksheet with the year's documents, especially if the report shows a corrected distance without its full explanation. The accountant report checklist helps you identify these adjustments in the handoff. A short, honest correction note is more useful than a perfectly tidy log that hides how the numbers changed.