How it works
Select at least two FIT files. UP + DOWN detects their order and checks that they can be joined before creating your download locally.
What is preserved
The merged file retains the activity records, timing, distance progression and compatible sport information needed for a coherent activity. Device-specific and developer data are not retained.
When to use a FIT merger
Use it when one ride, run or other recorded activity was saved as consecutive FIT files and you want to combine the compatible parts into a single activity.
Privacy
FIT processing happens in your browser. Files are not uploaded, stored or sent to analytics. Read our privacy policy.
Current limitations
Files must not overlap and must use the same sport and sub-sport. The merger currently accepts FIT activity files only.
FAQ
Are my FIT files uploaded?
No. They are read and merged locally in your browser; the resulting download is created on your device.
Can I merge Garmin activities?
Yes, when the exported FIT activity files are compatible and consecutive. The tool checks compatibility before merging.
Why can’t two files be merged?
They may overlap in time, use different sport types, or contain data that cannot be validated as a compatible FIT activity.