Mileage guide
How to Review Duplicate Trips After a Mileage Import
By FlatMile ·
At a glance
Review suspected duplicate mileage trips on a copy of your files, compare more than distance, and remove a row from the working total only when you can explain why it repeats the same journey. Two trips on the same date can be legitimate, and matching miles alone is not a safe deletion rule.
This procedure is a spreadsheet and file review. It does not claim FlatMile has an automatic deduplication tool, an undoable bulk-delete action or a particular import merge rule. Follow the CSV import checklist before moving any corrected file into an app.
Preserve the inputs and establish the overlap
Keep the original exports in a separate folder. Record each filename, source app, export date, covered period, unit and row count. Name the review copy clearly so it cannot be mistaken for an untouched export.
If one file covers January through June and another covers June through December, June is the first overlap to inspect. An export created later is not necessarily a different set of trips. Conversely, the same filename does not prove identical contents.
Filter to actual journey rows before comparing them. The FlatMile sample CSV contains trip, band, total and note records. Summary and note rows must not be counted as additional drives.
Compare identity, direction and time
A stable reference can be useful when both files originate from the same exporter. Also compare vehicle, date, departure time, start, destination and distance. Different providers may generate different identifiers for one journey; an identifier without source context is not universal proof.
Normalize units and date interpretation in helper columns while leaving original values untouched. Do not rewrite ambiguous dates until you know whether the file uses month-first or day-first ordering. Note time-zone changes rather than assuming that two nearby timestamps mean different trips.
Worked duplicate-review example
All rows below are fictional and use the same vehicle and date.
| Row | Time | Direction | Miles | Review finding |
|---|---|---|---|---|
| A | 09:00 | Workshop to Client Q | 12.0 | Original morning trip |
| B | 09:00 | Workshop to Client Q | 12.0 | Same original reference repeated in second export |
| C | 10:15 | Client Q to workshop | 12.0 | Separate return journey |
| D | 15:00 | Workshop to Client Q | 12.0 | Documented second visit |
The initial total is 48.0 miles. Excluding B after confirming the repeated source record leaves 36.0 miles. Removing every repeated 12.0-mile value would wrongly discard C and D. The review decision depends on evidence, not an equal-distance formula.
If A and B instead show different purposes or distances, mark a conflict. Compare the originals and supporting records before choosing one. Do not select whichever version produces the larger claim.
Reconcile the output and preserve the explanation
Create a decision column with “keep,” “duplicate of row A,” or “unresolved conflict.” Store the excluded rows in the review workbook rather than destroying the only copy. Then compare counts and totals:
- Original journey count and mileage.
- Number and mileage of confirmed repeats excluded.
- Remaining journey count and mileage.
- Unresolved entries needing a decision.
Review a few beginning and ending dates after sorting to catch accidental row shifts. If you later import the corrected data, verify the destination count and sample records before continuing. For retention of the originals and review notes, use the mileage archive guidance.