Mileage guide
How to Start a Mileage Log Halfway Through the Year
By FlatMile ·
General US federal recordkeeping information, not individual tax advice. Tax treatment depends on your circumstances; consult a qualified adviser for your claim.
At a glance
Start a mileage log today with a dated opening reading and complete records for new journeys. Handle earlier months in a separate recovery worksheet. A log begun halfway through the year can improve the record from that point forward, but it does not automatically prove the trips you made before starting.
This guide is for building a workable record without disguising its boundary. If the business itself began midyear, distinguish that date from the date you first began logging; they may be the same or different.
Make the starting boundary explicit
While parked, record the date, vehicle, distance unit and current odometer. Save a supporting photograph if useful. Write a note such as “Detailed log begins July 15; earlier period under review.” That gives a future reader a clear explanation of what the file covers.
Choose a routine you can maintain: a notebook, the free mileage template or an app with regular review. Enter the purpose as well as the distance. Test that you can retrieve the records before relying on the method for months.
If using FlatMile, automatic and manual logging are free. Captured-drive details and classification, and all app CSV/PDF exports, require a subscription or eligible trial. Check the eventual reporting step as part of setup.
Keep three kinds of evidence distinct
Use this fictional organization for a July start:
| Period or record | Available evidence | Where it belongs |
|---|---|---|
| January through April | Old export from previous app | Preserved original plus reviewed copy |
| May through July 14 | Some job records, no complete log | Recovery worksheet with open questions |
| July 15 onward | Newly maintained journey log | Current record with stated start date |
Do not concatenate all three into an apparently continuous original log. A combined overview can be useful, but it should explain which entries were recorded at the time and which were reconstructed later.
The IRS recordkeeping overview emphasizes retaining supporting records. For the missing period, the recovery guide helps identify what calendars, invoices and old files can and cannot establish.
Avoid extrapolating a busy month across the whole year
Suppose your fictional July 15–December 31 log contains 2,400 business miles. Multiplying by two produces 4,800, but it does not establish 4,800 business miles for the year. Your workload, holidays, vehicle use and customers may have changed.
IRS Publication 463 discusses sampling only where other evidence demonstrates that recorded periods represent the year's use. A late-start log alone does not meet that condition. Discuss any proposed reconstruction or sampling with your preparer rather than turning a projection into recorded trips.
Separate annual vehicle mileage from the new log
A July opening odometer and a December closing reading describe movement during that interval. They do not establish January-to-December movement. Look for earlier dated readings in retained records, and label the source and date accurately.
For example, a service reading from February 3 is evidence of the reading on February 3; it is not automatically a January 1 reading. Preserve that distinction in the handoff even if the difference seems small.
Make the first week's review deliberate
At the end of the first week, compare the new log with actual appointments. Check the vehicle, units, return journeys and personal segments. Add missing purposes while you can explain them, and save a copy you can open outside the capture workflow.
Continue the new routine while investigating the older gap. Before year end, use the closing checklist and tell your accountant precisely which periods are complete, reconstructed or unresolved. A clear partial record is more useful than an apparently complete one built on unlabelled assumptions.