FIT File Combiner
Stitch split recordings into one FIT with a continuous timeline.
Files stay on this device
Combine FIT files when a watch, bike computer, or interrupted recording has split one workout into several parts. Select the activity files in ride order, arrange them in the list, and create one combined FIT download. The joiner makes a continuous timeline so the recordings can be reviewed or imported as one activity in compatible software.
The FIT format stores timestamped records and may include GPS, heart rate, cadence, power, and other sensor data. Switchback combines the records in your browser and keeps source fields when they are supported, without uploading your activities or requiring an account. Check that the files belong to the same session and are ordered correctly before combining. Your originals remain unchanged, and you can download the merged result as a separate file.
When to combine FIT files
A FIT file combiner is useful when one workout was saved as more than one recording. A watch may split a long ride after a battery interruption, an accidental stop, or a device restart. Combining the parts can make one continuous activity that is easier to review, archive, and import into a compatible service.
You can also join FIT segments from a multisport session when you want the records in a single file. Choose only files that belong to the same event and put them in the order they happened. Separate activities from the same day should usually stay separate; combining unrelated recordings can create a misleading timeline and activity summary.
What the FIT file combiner does
The combiner reads the records in each source file and writes them into one new FIT download. It joins the next recording one second after the previous file ends, avoiding a backwards timestamp while shortening any real pause between files. The original FIT files are not edited, so keep them if you need the exact gap or want to make a different combination later.
GPS points, timestamps, elevation, heart rate, cadence, and power can be retained when they are present in the inputs and supported by the output. The tool cannot invent a missing section, fill an unknown pause, or reconcile duplicate records automatically. Before combining, confirm that the selected files overlap or continue in the expected order and that each one belongs to the activity you are rebuilding.
How to combine and import the result
- Locate the original FIT files for the split activity and keep a backup of each.
- Select all parts below and arrange them in the order the ride or multisport session happened.
- Run the combiner and download the new FIT file. Processing stays in your browser.
- Open Garmin Connect or Strava and use its activity file import flow to add the combined file as a new activity.
- Review the imported route, timestamps, and sensor values before sharing or deleting any local copies.
Services can differ in how they handle imported FIT files, so check the new activity after upload. If the import is rejected, retain your original recordings and try importing each part separately or choose a supported export format. Browse the FIT file converters for other ways to prepare activity files.
Your file is processed in your browser and never uploaded.
What this format is
Use this when a watch split a long ride into two files. The combiner writes one FIT with a continuous timeline.
How to get the file
- From Garmin Connect
- 1. Export each original FIT, drop them together, import the combined file.
- From Strava
- 1. Strava will treat this as one activity if you upload the combined FIT.
What is kept and what is lost
| Kept | Lost or missing |
|---|---|
| Every record from each file, in order | The gap between files is collapsed to one second |
1Select a file
2Set options
Nothing to set. Run when the file is ready.
3Run
Select a file first.
Questions
When should I combine FIT files?
Combine FIT files when a watch split one activity into multiple recordings, or when you need compatible parts joined into one session. Put the files in activity order before combining. The tool preserves each readable record and joins the timeline with a short gap between consecutive recordings.
How do I combine FIT files from a multisport activity?
Choose the FIT segments that belong to the same multisport session, then arrange them in the order they happened. The combiner joins their records into one FIT file. Check the resulting timeline and activity fields before importing, since the output cannot restore data missing from an original segment.
Can I upload the combined FIT to Garmin Connect or Strava?
The combined file is a standard FIT download that you can try to import as a new activity using the destination service’s file import flow. Availability and accepted fields can depend on the service and source data. Keep the original recordings and review the imported activity after upload.
What happens between the combined recordings?
The combiner places the next recording one second after the previous file ends to avoid a backwards jump in the activity clock. Any real pause between source files is therefore shortened in the combined timeline. Keep the originals if preserving the exact recording gap matters.
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