FIT file viewer

What is a FIT file?

FIT files store records from fitness devices, such as time, distance, heart rate and GPS coordinates.

How to use

1. Click “Choose a FIT file” or drag a file into the file area. Select one uncompressed .fit file, up to 25 MB. Decoding starts automatically.
2. Review file information, activity metrics and message-group counts in “File overview”. Unrecorded data appears as a blank value or “Not in file”.
3. In “Data charts”, select a metric and elapsed time or distance as the horizontal axis. Options require enough records in the file.
4. In “FIT messages”, select a group to view its table. Search field names or values within that group, and use Previous and Next to change pages.
5. In “3D route”, drag the drawing or use the controls to change the view. Elevation scaling requires altitude records. No route is drawn without enough positions.
6. Check the CRC result and decoding warnings in “Integrity & diagnostics”. Export JSON saves all decoded messages; Export group CSV saves the entire selected group, regardless of search filtering. Clear starts over.

Your data stays on your device

File reading, decoding and exports happen in your browser. Files and decoded contents are not uploaded. Charts and routes depend on the records present in each file.