From a file a day to one trip
- Collect the file of every day. Download each day's original from wherever it is kept; the export guide shows where watches, bike computers and the big platforms keep them. If you saved a day in two or three pieces, bring all of them.
- Drop the lot into the box above, in any order. One merge takes 2–30 files, so a fortnight with a couple of files per day still fits. The tool lines them up by time.
- Read the notice, then tick the box. When the files span more than one day, a notice beginning These files cover 3 days (with your own count and dates) appears, and the download stays locked until you tick These are days of one trip. Merge them into one activity.
- Download FIT. It is already selected. For a trip, keep it that way; the platform section below explains what goes wrong with GPX and TCX over several days.
- Clear out the daily activities, then upload. Under the button the page reminds you: Delete the original activity for every day on Strava or Garmin Connect before uploading this file, or it may be rejected as a duplicate.
Everything above runs inside this browser tab. The day files never leave your phone or computer.
How the nights are handled
FitMerge looks for nights on the joined timeline. A stop counts as one when it lasts more than 2 hours and runs past midnight, or when it is longer than half a day whatever the clock says. It finds them between files and also inside a single file, for a device that was paused overnight rather than saved.
In the merged file every night is a pause. Moving time and the averages leave the nights out, and the distance is only what your devices recorded, so a night in the tent doesn't pull your average speed down. The span from the first start to the last finish still contains the nights, of course.
Two limits apply. Neighbouring days may be at most 48 hours apart, enough for one rest day in town between two riding days. The whole trip, from the first file's start to the last file's end, may last at most 14 days. Past either limit the page explains which one and won't merge; split the trip into two shorter merges instead.
What this version leaves out
Merging whole trips is new, and some things you might expect are not there yet. They are listed here so nothing surprises you after the upload.
- No day-by-day view. The notice gives the number of days and their dates. The totals on the page describe the trip as one block.
- Laps follow your files, not your days. Each file brings its own laps, and a file without any, as a GPX file is, counts as a single lap. So the final lap before each night stretches across it, and that lap's total time includes the hours you spent asleep.
- Every change redoes the whole merge. Ticking a box or choosing another format rebuilds the trip from all its files. A computer barely notices; on a phone, two weeks of data can make the page hang for a moment each time.
- All points are kept. The merged file holds every recorded point of every day, which for Garmin Connect can be too many, as explained next.
Long trips on Strava and Garmin Connect
File size. Strava's upload help requires files of 25 MB or less, and Garmin Connect accepts GPX and TCX up to 25 MB too. GPX and TCX write out every point as text, so by our estimate from our own files, a week or longer logged once a second can go over that. The same trip saved as FIT is many times smaller.
Pauses. GPX has no way to mark a pause. When we imported a merged GPX into Garmin Connect for our own tests, its time ran from the first point to the last with the breaks included, which on a trip would add every night to the activity's time. For Garmin Connect, download FIT: it stores each night as a pause.
Point limit. Garmin's page on importing activity files says a file must contain fewer than 99,999 data points. By our own estimate, a device logging every second gets there after about four days on the move, and FitMerge doesn't warn you when a merge goes past it. Devices that record less often take longer to reach it.
Garmin's own advice. For rides that run over several days, Garmin's help on recording long activities on an Edge recommends saving a separate activity for each day or stage, and points to Garmin Epic for grouping them. If Garmin Connect is your main record, that is the approach Garmin describes. A merged file is for when you would rather see the trip as one entry.
Questions
Will the kudos and comments on each day survive?
Not on Strava. Its article on combining activities tells you to remove the originals before uploading the merged one, and their kudos and comments disappear with them. Copy any comment you care about before deleting.
What is the grey dashed line on the map?
Each file is drawn in a colour of its own, and a grey dashed line links the end of one file to the start of the next. Between two days, that is the hop from where you stopped in the evening to where you set off in the morning. If the next day begins more than 1 km away, say after a ferry or a bed off the route, the page adds a line like Day 2 starts … km from where day 1 ended. The merge still goes ahead.
Does the height difference between days count as climbing?
Not unless you ask. By default the step in elevation from the end of one file to the start of the next is left out of ascent and descent. The Options box has a setting that counts elevation change across gaps; turn it on if you covered that difference under your own power, and leave it off after a bus or a lift.
Can a single day be split over several files?
Yes. Save at lunch, at a café or after a puncture and start again: bring every piece. Only a long stop past midnight or one longer than half a day starts a new day, so the pieces of an afternoon stay in the same day. If one of those stops ran beyond 2 hours, the same tick box covers it.
My trip is longer than 14 days, or one gap is over 48 hours. What now?
The page names the problem and refuses to merge. Merge the trip in sections that each stay inside both limits, or let the longest break be the boundary between two activities.