FIT File Viewer
Free online FIT file viewer. Open Garmin and sports-device .fit activity files to see the session overview, heart rate, speed, altitude records, GPS track, laps and export everything to CSV — parsed locally in your browser.
What is a FIT file?
FIT (Flexible and Interoperable Data Transfer) is the binary format used by Garmin, Wahoo, Zwift and most sports devices to store workouts: GPS points, heart rate, speed, altitude, laps and device metadata in a very compact file.
How do I open a .fit file here?
Click the upload area or drop your .fit file onto it. The file is parsed in a background worker and the overview, records, track and laps appear within a few seconds.
Is my activity data uploaded anywhere?
No. The file is read and decoded entirely inside your browser tab using a Web Worker. Nothing is sent to any server, which matters for private home addresses visible in GPS tracks.
What information does the overview show?
Sport type, start time in your local format, total duration, distance, calories, average and maximum heart rate and total ascent. Rows for values not present in the file are hidden automatically.
Why does the records table show only some rows?
Long activities can contain thousands of second-by-second records. The table is throttled to at most 200 evenly spaced rows so it stays fast to scroll — the CSV export always includes every record.
How is the GPS track drawn?
The track is a normalized SVG polyline computed from the latitude and longitude of each record. No map tiles are loaded, so it works offline and reveals nothing about the map style or provider.
What does the CSV export contain?
Every record with timestamp, elapsed seconds, heart rate, speed in km/h, altitude, temperature, distance, cadence, power and GPS coordinates when available, written as UTF-8 with a BOM so Excel opens it correctly.
My file shows an error — why?
Either the file is not really a FIT export (the viewer checks the .FIT signature bytes) or it is corrupted or uses an unsupported profile version. Try re-exporting from the original device or application.
Which devices and file types are supported?
Any standard FIT activity file: running, cycling and swimming sessions from Garmin, Wahoo, Zwift, Coros, Polar and similar devices, including files with multiple laps and enhanced altitude or speed fields.
How to Use FIT File Viewer
This FIT viewer decodes Garmin and sports-device activity files entirely in your browser with a Web Worker. See the session overview, browse records, follow the GPS track and export everything to CSV — your file is never uploaded.
- Click the upload area or drop a .fit activity file onto it; parsing starts immediately.
- Read the overview: sport type, start time, duration, distance, calories, average/max heart rate and total ascent (rows appear only when the file contains them).
- Scroll the records table with heart rate, speed, altitude and temperature — throttled to 200 rows; the note shows how many of the total are displayed.
- Check the GPS track drawn as an SVG polyline, plus the lap table with start, duration and distance per lap.
- Press Export CSV to download every record as a UTF-8 CSV that opens directly in Excel.
The records table is a sample for quick inspection — always use Export CSV when you need the complete second-by-second data for analysis.
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