Combine Strava Activities or Merge Two Garmin Activities
Accidentally stopped your Garmin, Wahoo, or Strava recording mid-ride or mid-run? This tool lets you combine Strava activities, or the underlying FIT files from any device, into a single continuous activity, with correct combined distance, time, and heart rate, entirely in your browser. Nothing is uploaded to any server.
Click to choose files, or drag and drop your Strava/Garmin .fit files here
Files stay on your device. Nothing is uploaded.
Use the arrows above to set which activity is first, second, and so on. Your actual GPS and heart rate data will always play back in real chronological order, this setting controls lap order and which segment’s stats are counted first.
Leave blank to use the default pattern: ActivityType_DDMMYY_All.fit
How to Combine Strava Activities With This Tool
This tool lets you combine Strava activities, or the raw FIT files behind them, from two or more separate recordings into a single continuous activity. It is built for the exact situation where a GPS watch or bike computer got accidentally stopped mid-workout, restarted, and ended up creating two (or more) separate activities on Strava for what was really one ride, run, or hike.
Why Combine Strava Activities From a Paused Recording?
Strava, Garmin Connect, and most training platforms treat each uploaded activity as its own workout. If your session got split in two, your stats, calories, and elevation gain get split too, and your training log shows two shorter workouts instead of the one long one you actually did. Combining the files back into one fixes the record.
All processing happens locally in your browser using JavaScript. Your FIT files, GPS coordinates, and heart rate data are never uploaded to a server, logged, or stored anywhere. The moment you close the tab, everything is gone.
What This Tool Does
Steps to Combine Strava Activities
Add your files
Drop in 2 or more .fit files exported from Strava, Garmin Connect, Wahoo, or your device’s memory card.
Check the order
Files are read chronologically by default. Use the arrows to change which segment is treated as first if you need to.
Combine Strava Activities
Click Combine Strava Activities. The tool merges records, laps, and stats into a single valid FIT file in seconds.
Download and upload
Download the combined file, then re-upload it to Strava, Garmin Connect, or TrainingPeaks like any normal activity.
How Distance, Time and Heart Rate Are Combined
Every FIT file stores a session summary alongside the raw GPS and sensor records. This tool rebuilds that summary rather than just concatenating files, so the combined activity’s stats are accurate, not just its map.
segment_2.distance += segment_1.total_distance
Each file’s distance track starts back at zero, so every later segment gets the previous segments’ total distance added to it, keeping the combined track continuously increasing.
total_timer_time = sum(file.total_timer_time)
Timer time from each file is added together. The real-world gap between when you stopped and restarted recording is preserved as a pause, not deleted or counted as moving time.
total_calories = sum(file.total_calories)
Calories, total ascent, and total descent are added directly across every file included in the merge.
avg_hr = Σ(file.avg_hr × file.timer_time) ÷ Σ(file.timer_time)
Average heart rate is weighted by how long each segment lasted, so a short 5-minute segment does not skew the combined average as much as a 30-minute one. Max heart rate is simply the highest value across all files.
Combine Strava Activities: Quick Summary
Same activity type
Works best when combining files of the same sport, cycling with cycling, running with running, and so on.
Any device brand
Works with FIT files from Garmin, Wahoo, Suunto, COROS, and any device that follows the standard FIT format.
Nothing leaves your device
Every calculation runs client-side. Files are never sent to ConvertNow.Tools or any third party.
FAQ: Combine Strava Activities
Export the FIT file for each split activity (from Strava’s activity menu, or straight from Garmin Connect), upload both into this tool, set the order if needed, and click Combine Strava Activities. Download the merged FIT file, then upload it back to Strava as a new activity and delete the two originals to avoid double-counting your stats.
Yes. FIT is a standardized format used by Garmin, Wahoo, Suunto, COROS, Polar, and most GPS sports devices, so files from different brands can generally be combined. The tool reads the raw FIT structure directly rather than relying on brand-specific quirks. What matters more than brand is activity type, combining a cycling file with a cycling file works best.
It’s kept as a real pause rather than deleted. The combined file’s total elapsed time spans from the start of your first activity to the end of your last one, including the gap, while total moving (timer) time only counts the time you were actually recording. This mirrors what actually happened and matches how Garmin’s own auto-pause feature represents stopped time.
There’s no hard limit built into the tool, you can add two, three, or more files. In practice most people are combining two files from a single accidentally-split workout, but the merge logic works the same way for any number of segments, and each one becomes its own lap in the combined file.
Your GPS track, heart rate, and other point-by-point data are always played back in true chronological order based on each record’s real timestamp, so the map and graphs are always correct regardless of upload order. The order you set with the up and down arrows controls which segment is labeled Lap 1 versus Lap 2, and which segment’s distance is treated as the base that later segments are added on top of.
The tool will show a warning if it detects mismatched activity types, but it won’t stop you from combining them. That said, most training platforms expect one sport per activity, so combining a run with a ride will likely produce an odd-looking result in Garmin Connect or Strava. This feature is really meant for combining two segments of the same workout.
You can type your own file name before downloading. If you leave it blank, it defaults to a pattern like Cycling_040826_All.fit, made up of the detected activity type, today’s date in DDMMYY format, and “All” to indicate it’s the combined file. The .fit extension is always added automatically if you leave it off.
Yes. The entire merge happens locally in your browser using JavaScript, your FIT files, GPS coordinates, and heart rate data are never uploaded to a server, logged, or stored anywhere. Everything is discarded the moment you close or refresh the page.