What is FIT File Tools?
FIT File Tools is a set of free web tools for editing Garmin FIT files, built by a software developer and bike racer who wrote them for his own files and put them online. You pick a tool, drop in a file, press Go and download the result. There's no account and no sign-up.
Strava's help names it twice. The article on the "corrupted time data" upload error walks you through its Corrupt Time Fixer, and the article on merging activities suggests it for combining FIT files, since Strava can't merge activities itself. The fixed file comes back with "fitfiletools" in its name, and that's the one you upload.
Key Features
Fixing a file Strava rejects
The Corrupt Time Fixer is for files whose timestamps suddenly jump into the future. It has a Normalize Time option for large jumps, which the site says to try only if the plain fix has failed. If the fixer doesn't work, Strava's article moves you on to the Time Adjuster, which sets the file's date and time directly.
Joining and merging
The File Combiner joins several files into one activity. The site's example is the ride to a race, the race and the ride home. The Field Merger is a different job: it copies heart rate, GPS, power or cadence from one file into another by matching timestamps within five seconds, then recalculates averages, maximums and normalized power. That's for two devices recording the same session.
Cleaning up what was recorded
The Section Remover cuts out a stretch you select, such as the drive home you forgot to stop recording. The Peak Remover strips records above a power or heart rate threshold you set. The Power Booster adjusts all power values for a mis-calibrated meter. The Field Stripper removes a field such as power altogether, and the Break Remover fills gaps of more than five seconds with zero-speed rest records so charts and map traces don't jump.
Adding what's missing
The Start Extender adds the part of a ride your device missed: you trace the route on a map, enter when you really started, and it adds a GPS record per second. The Elevation Setter puts a total climb on an indoor ride or treadmill run.
Changing labels and formats
The Device Changer changes the device the file says created it, which the site suggests if you want Strava to treat a barometric device as one without a barometer. The Sport Changer rewrites the sport, subsport and activity name. The converter exports to GPX, TCX, JSON or CSV, and the FIT Inspector shows the raw messages inside a file.
What goes to Strava
Nothing automatic. The documented route is the one in Strava's articles: export your file or find it on your computer, fix it here, delete the original activity if there is one, and upload the new file on Strava. The site also shows a Connect with Strava button in its footer and an Upload to Strava button after a tool has run. Strava's help doesn't describe either, and the site's FAQ only mentions a "replace" option when uploading. The upload screen warns that replacing deletes the duplicate activity, with its comments and kudos. So plan on doing the upload yourself. The documented route reads nothing from your Strava account; the file comes from you.
Who It's For
- Anyone stuck on Strava's "corrupted time data" error, which is how many people find this site
- Riders with a recording split into pieces or a stretch they want gone from the file
- People whose power meter or heart rate strap spiked and threw off their averages
- Anyone with two devices on one ride, where one has the GPS and the other has the heart rate
What it doesn't do
It works on FIT files, and that's the only input. If your activity is a GPX or TCX, this isn't the tool, and exporting to those formats is one way only.
The route Strava documents doesn't change the activity on Strava. A fixed file is a new upload, so kudos and comments on the old activity go if you delete it first, which Strava's merge article warns about. The site won't rescue every file either: its blog says the Corrupt Time Fixer fixes most cases of that fault, not all of them.
The tools run on the site's server rather than in your browser, so your file does leave your computer. The Blog on the site hasn't had a post since January 2017, though the tools have kept changing.
What happens to my files?
The site says uploaded files sit in temporary storage and are automatically deleted within 24 hours, and aren't used for anything except processing your request. Transfers are over HTTPS. It also logs anonymous usage such as which tools are used, file sizes and referral sources.
Strava says my fixed file is a duplicate. Why?
The site's FAQ says that error means the file has already been uploaded. Delete the existing activity on Strava, then upload the modified file. The FAQ also offers a "replace" option when uploading; the site's upload screen warns that it deletes the old activity, comments and kudos included.
What is Carb Master?
A free Connect IQ data field from the same maker, for touchscreen Garmin Edge computers. You log what you eat on the bars and it tracks how far behind your hourly carb goal you are. It writes that to the FIT file, and the site's Fuel Gauge charts it after the ride.
