Convert FIT to TCX.

Field notes

Why TCX instead of GPX?

GPX has no standard field for power. TCX does (Watts, in the ActivityExtension schema), plus heart rate and cadence as first-class elements. If your target app accepts TCX and your ride has power data, this is the lossless-er choice.

What does the output look like?

A single activity with one lap (total time and distance computed from your records) containing every trackpoint: time, position, altitude, cumulative distance, heart rate, cadence, speed and watts.

Is my data private?

Your file is never written to disk. It is parsed in memory, converted, sent back, and garbage-collected. No accounts, no tracking pixels, no “files are deleted after 24 hours” fine print — there is nothing to delete.