GPX vs TCX vs FIT: what’s the difference?
All three hold your GPS track, but they differ in what else they carry and which apps and devices prefer them. Here’s the short version.
GPX — the universal format
GPX is plain XML and is read by almost everything: Strava, Garmin, komoot, phone apps and websites. It stores location, elevation and time, plus heart rate and cadence via extensions. It’s the best format for sharing a route or moving data between apps.
TCX — Garmin’s richer XML
TCX is also XML but adds structured laps and per-point sensor data (heart rate, cadence, power). Garmin Connect exports it for some activities. It’s useful when you want to keep lap structure, but it’s more verbose than GPX and less widely supported.
FIT — the device-native binary
FIT is the compact binary format that Garmin, Wahoo and Coros devices actually record. It packs the most data (every sensor, per second) into the smallest file, but it isn’t human-readable and not every app accepts it.
How to convert
You can convert any of these to GPX for free, in your browser — heart rate and cadence are preserved: