How it works
Three steps, no upload
Everything runs on your device. The merged file is ready in seconds, even for a long day out.
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Drop the files
Two to ten FIT, GPX or TCX files from the same activity, in any order. Zip and gz archives are fine.
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Check the result
The map and the before-and-after table show distance, moving time, elevation, heart rate and power for each part and for the merged activity.
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Download and upload
Save one FIT (or GPX or TCX) and upload it to Strava, Garmin Connect, Komoot or wherever you keep your activities.
Sound familiar?
When an activity gets split
- Your Garmin, Wahoo or watch ran out of battery halfway, and you finished on your phone.
- You pressed Save instead of Pause at a café, and started a new activity afterwards.
- The app crashed or the watch rebooted, so the run is in two files.
- You recorded on two devices back to back and want one activity instead of two.
Either way you end up with two Strava activities, broken totals and missing segments. FitMerge joins the parts into one file: the gap between them counts as a pause, cumulative distance continues, and laps, heart rate, power, cadence, temperature and your device's identity are carried over, so Strava and Garmin Connect treat the result like a normal activity.
FAQ
Questions
Is FitMerge free?
Yes. There is no account to make, no ads and nothing to pay. If it rescued a ride or a run, you can buy me a coffee.
Do my files get uploaded anywhere?
No. Reading, merging and writing all happen in your browser, and your files never leave it; the merged file is saved straight to your device. Besides the map tiles from OpenStreetMap, the page only sends anonymous usage counts, such as "merged 3 files". See the privacy note.
Which files and devices work?
FIT, GPX and TCX files, also inside .zip or .gz archives, and you can mix formats in one merge. Tested with Garmin Edge, Forerunner and fenix, Wahoo ELEMNT, Hammerhead Karoo, COROS, Suunto, Polar, Zwift, and GPX or TCX exports from Strava, Garmin Connect, Komoot and Apple Watch. Runs, walks and hikes work the same way as rides.
How do I get the files from Strava or Garmin Connect?
Strava: open the activity, click the three dots and choose Export Original (or Export GPX). Garmin Connect:
open the activity, click the gear icon and choose Export File for the original FIT file (older layouts call it
Export Original), or Export to GPX / TCX. From a Garmin device over USB, the FIT files are in Garmin/Activities
(on watches it may be GARMIN/Activity). The
export guide has the steps for these and for Wahoo, Karoo, Zwift, COROS, Polar, Suunto, Komoot and Apple Watch.
What should I do with the two original activities on Strava?
Delete both originals before you upload the merged file. Strava may reject an upload that covers the same time as an activity you still have as a duplicate, and if you kept the originals your weekly totals would count the ride twice.
Will Strava keep the elevation from my device?
Yes, as long as you download FIT and Strava recognises your watch or bike computer as one with a barometric altimeter. The merged file keeps your head unit's identity, so Strava can use the elevation it recorded. For GPX uploads Strava recalculates elevation from its own terrain data.
How is the time between the two parts counted?
As a pause. Moving time, distance and averages come from the recorded parts only. Gaps over 2 hours ask for confirmation; gaps over 12 hours are not merged. You can optionally include the elevation change across the gap.
Can I merge runs, hikes or swims?
Runs, hikes and walks: yes, and any other single-sport activity as long as the parts are the same sport. Swims and triathlon files are not supported. If the parts disagree or don't say their sport, you pick one before downloading. TCX can only say Running, Biking or Other, so download FIT for hikes and other sports.
Guides
Guides for your situation
- Merge two Strava activities into one Strava can't join activities. Export the parts, merge them here, upload one.
- Combine two Garmin Connect activities into one Connect's Trim shortens one activity but can't join two. Take the parts out as files and import a single FIT.
- Merge FIT files into one activity Laps, sensors and the device come through when several .fit files from one outing become one.
- Merge GPX files from one activity For recorded tracks, where every point has a time; a planned route is turned away.
- Battery died mid-ride or run? Get one activity back Your device gave out and the phone took over. Put the two recordings back together.
- Ended your activity by mistake? Join the two parts Pressed Save or Finish when you meant Pause? Join the part before and the part after.
- How to get your activity files Where your watch, bike computer or app keeps the FIT, GPX or TCX file.
Support FitMerge
Free, no ads, and your files stay on your device. If it saved a ride or a run for you, a coffee keeps it that way.