What is a FIT file?
A .FIT file is usually a Garmin Activity File. It stands for Flexible and Interoperable Data Transfer. Devices like sports watches and bike computers create these files to store GPS tracks, heart rate, and speed. Garmin created the Garmin FIT Protocol, but many brands use it. Sometimes, a .FIT file is an astronomy image data file used by NASA.
How to open FIT files?
You can open fitness .FIT files with Garmin Connect or Strava. If you have an astronomy file, you need special software like FITS Liberator. Because .FIT has multiple possible meanings, we recommend using viewer.online/fit to identify the actual format of your file. viewer.online/fit analyzes .FIT files to identify their exact format and creator software, shows which programs can open the file, and usually previews it.
Best practices and troubleshooting
Broken .FIT files are common if a device loses power during an activity. Tools like FIT File Tools can fix them. If you need to use the data in a text editor or spreadsheet, you should convert it. You can convert fitness data to .CSV, .GPX, or .TCX formats on convert.guru.
Software and tools
Common tools include Garmin Connect and GoldenCheetah for fitness data. For scientific files, use NASA tools.
Summary
viewer.online/fit directly opens and previews .FIT files in the browser, eliminating the need to install software or troubleshoot compatibility issues.