FitConvert

12/18/2025

Understanding FIT Files: The Backbone of Modern Fitness Tracking

Why devices like Garmin and Wahoo rely on FIT for high-resolution workout data

What is a FIT file?

A FIT file (Flexible and Interoperable Data Transfer) is a binary workout file format developed by Garmin. It is widely used by Garmin devices and many third-party fitness platforms to store detailed activity data such as heart rate, cadence, power, GPS position, and device metrics.

Because FIT files are compact and structured, they are ideal for recording high-resolution workout data from wearables.

What data does a FIT file contain?

FIT files can include:

  • GPS tracks
  • Heart rate data
  • Power and cadence
  • Elevation
  • Laps and splits
  • Device metadata
  • Sensor information

Unlike text-based formats, FIT files are optimized for efficient storage and fast processing.

When should you use a FIT file?

FIT files are best when you:

  • Record workouts on Garmin devices
  • Need precise sensor and performance data
  • Upload activities to platforms like Garmin Connect or TrainingPeaks
  • Want smaller file sizes with richer data

Limitations of FIT files

While powerful, FIT files have a few downsides:

  • They are not human-readable
  • Manual editing is difficult
  • Not all platforms support them

If you need compatibility with non-Garmin tools, converting a FIT file is often necessary.

Converting FIT files

With FitConvert, you can convert FIT files into TCX and GPX formats so your workouts remain compatible across platforms.

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