Try to repair a damaged FIT activity file on your own computer
Check your file for free in your browser, then buy the downloadable tool if you want to save repair attempts.
A$6 once, tax included. Download a ZIP containing one HTML tool, instructions and a licence. Unzip it, open FITRepair.html in your desktop browser and use it offline. Repair as many of your own files as you need, with no subscription or charge per file. JavaScript must be enabled.
The free check and paid tool use the same repair engine. Buying the download adds the ability to save repaired files; it does not promise a better repair. After buying, choose your original file again in the downloaded tool.
What it attempts to repair
Damaged or missing checksums, some damaged headers and recordings that end partway through a message. It can skip damaged stretches and rebuild a missing end summary from surviving activity data. Your original file stays unchanged, and you save the repair attempt as a separate FIT file.
Your activity file is processed in your browser and is not uploaded. The downloaded tool runs without an account or internet connection. Buying and downloading it requires an internet connection. Try the free check in your desktop browser before buying. Automated browser checks used Chromium; other browsers and phones are unverified. Maximum file size: 60 MB.
Try the free check first
Choose your FIT file in the free browser check. Read its diagnosis and any warning about lost data before deciding whether to buy. The check may be unable to repair your file. Keep your original, even if the check offers a repair.
Limits
Missing recording data cannot be recovered. A damaged stretch may be dropped, and damage near the start can leave most or all of an activity unreadable. The tool cannot always detect how much data it lost.
A file that opens can still contain wrong values. Rebuilt distance, duration and averages are estimates, the sport may become generic, and lap or session totals can disagree. Compare the first and last timestamps shown by the tool with when you recorded the activity; they are in UTC and their span is not moving time. After opening a saved repair in an activity viewer, or after an accepted upload, compare its distance, duration and activity details with what you recorded. The tool does not display distance or duration. The tool repairs file structure; it does not assess training or health data.
The tool does not merge activities or edit them. It leaves structurally intact files alone. It does not run the Garmin FIT SDK or an independent decoder on your repair, so a repair attempt can still fail to open elsewhere.
Acceptance by Strava and Garmin Connect has not been confirmed. It is independent of those services and of device manufacturers. Real Zwift files have not been tested.
Download FIT File Repair v0.2.0
Stripe, through Link, handles payment and sends your receipt. After payment, the download page provides the ZIP. Keep that page's address so you can download again. If you lose it, contact support with your receipt. Your purchase permits this version on your own computers for unlimited repairs of your own activity files; redistribution is not permitted.
Within 30 days of a one-off purchase, ask for a full refund, no questions asked, under our refund policy. A refund revokes the store download link; files already saved on your computer cannot be revoked.
Privacy and support
The offline tool makes no network requests and stores no activity data. Saved repaired files remain on your computer. This website uses Cloudflare visit analytics; payment details are handled by Stripe.
Questions or a download problem? Contact [email protected]. Built and maintained by Madrasco with AI agents. Support replies may be AI-assisted; you can ask to reach the human owner.