FIT File Editor fixes a run, a ride, or any other workout in your browser, so you can send a clean copy to Strava, Garmin Connect, or wherever you log your training. It's free, and the file never gets uploaded.
The whole activity sits on one timeline, like a video editor for your workout: the map on top, every data stream below, and your edits previewed live. Crop out a part you don't want, like a warm-up or the drive home you forgot to stop recording. Strava only lets you trim the start and end of an activity, so you need a tool like this to edit or cut something out of the middle. Drag across it, hit Cut, and the laps and totals sort themselves out.
Bad data is just as quick to clean up. Cap a heart rate spike from a dry strap, smooth a power dropout, or pull a wandering GPS point back onto the road. You can also change the device or sport, shift the start time, join two recordings into one after a watch dies partway, or rescue a file that won't upload after a crash.
Jump straight to what you want to do:
Building something with FIT files? Read the FIT format reference for developers and AI agents.
Garmin, Wahoo, COROS, Suunto, Polar, Hammerhead, Zwift, Apple Watch through HealthFit, and anything else that writes a standard .FIT file. Runs, rides, swims, hikes, walks, ski days, rows, gym sessions: if it came off a watch or bike computer as a .FIT, it opens here.
FIT stands for Flexible and Interoperable Data Transfer, the format Garmin built to pack a whole workout into one small file. It records your position, heart rate, power, cadence, and more a few times a second, plus laps and a summary, so it holds far more than a plain GPX track. Nearly every watch and bike computer writes it, and Strava, Garmin Connect, and TrainingPeaks all read it, which is how it became the common language for activity data.
FIT File Editor was built by an ultrarunner and triathlete who kept needing to fix their own files. Fixing a file used to mean a different single-purpose tool for every problem, and none of them showed you what you were changing. This one works the way a video editor does: the whole activity on one timeline, where you cut and fix what you need and export a clean file. That idea still drives every feature.
Step-by-step answers to the problems that bring most people here, in the FIT file guides:
A few other places to view, fix, or convert activity files, or read the full comparison of FIT file tools:
Your files never leave your browser. What the site does count is in the privacy notes.