Free online FIT to TCX converter

A training platform, older Garmin-compatible application, or analysis tool may accept .tcx but reject .fit, requiring an export before an activity can be imported or shared. TCX also makes activity data easier to inspect or edit as text, although the converted file is usually larger and may contain less sensor data.

What FIT is

FIT (Flexible and Interoperable Data Transfer) is a compact binary format designed for sports and fitness data. Garmin devices and services use it, as do products from Wahoo, Polar, Suunto, COROS, and other manufacturers.

A .fit activity can contain timestamped GPS positions, time, distance, speed, heart rate, cadence, cycling power, elevation, laps, sessions, device information, nutrition events, and manufacturer-specific fields. The exact contents depend on the device and the recording profile. FIT is generally smaller and more efficient than XML, and it often preserves more device-specific information than an interchange format such as TCX.

What TCX is

TCX (Training Center XML) is a human-readable XML format originally created for Garmin Training Center. An activity TCX normally contains activities, laps, and track points with fields such as time, latitude, longitude, altitude, distance, heart rate, cadence, and calories. TCX can also represent courses and workouts, but those are different document types from an activity export.

TCX remains useful for software that supports Garmin XML but not FIT. Its element-based text structure can be inspected with a text editor and processed with standard XML tools. XML repeats field names and metadata, so a TCX file is commonly larger than the source FIT file. Garmin Training Center itself is discontinued and should not be treated as a current conversion tool.

Convert with desktop software

GoldenCheetah is a suitable desktop choice when the activity needs checking before export. It runs on Windows, macOS, and Linux and can import FIT activities and export supported activities as TCX.

1. Install GoldenCheetah, create or select an athlete, and open the activity database.
2. Use File → Import or the application’s activity import command, then select the original .fit file.
3. Open the imported activity and inspect the map, start and end times, duration, distance, laps, elevation, and available sensor streams.
4. Use the activity or file export command, usually under File → Export, select TCX, and save the result with a .tcx extension. Menu names can vary by GoldenCheetah version.
5. Import the TCX into the destination service and compare its totals with the original FIT activity.

Keep the original FIT file. It is the better archival copy and may contain developer fields, device metadata, running dynamics, cycling metrics, or other information that cannot be represented in the exported TCX.

Use an online converter

For a one-off conversion, the GoToes online converter can accept FIT input and produce TCX output. Upload the file, choose TCX as the output format, run the conversion, and download the generated file. Check the site’s current input and output list before uploading because web tools and file-size limits can change.

Do not upload activities containing sensitive home or work locations, personal identifiers, or private health information unless the service’s handling of uploaded files is acceptable. A local application such as GoldenCheetah avoids sending the activity to a third party.

Build a custom conversion

FIT-to-TCX conversion is not a reliable generic file-extension change. A programmer can decode FIT with Garmin’s FIT SDK or the Python fitparse package and generate TCX with an XML library, but fitparse is a decoder rather than a complete TCX writer. The converter must map FIT records into valid TCX activity, lap, track, and trackpoint elements, select the correct XML namespaces, and escape text and numeric values correctly.

A custom script also needs explicit rules for pauses, laps, missing coordinates, timestamps, units, and FIT developer fields. Testing against the destination service and validating the resulting XML are necessary before using the process in bulk.

Conversion limits

Standard time, GPS position, distance, altitude, heart rate, cadence, and calories usually transfer when the converter supports those fields. Power and advanced running or cycling metrics may be written only through vendor-specific TCX extensions, and many converters or receiving services discard them. FIT developer fields and manufacturer-specific records often have no TCX equivalent.

Conversion cannot restore missing GPS samples, recover data excluded during recording, infer the device’s pause logic, or correct an incorrect time zone. After conversion, check timestamps, activity boundaries, elapsed and moving time, laps, distance, elevation, heart rate, cadence, and power against the FIT original.

Some importers reject malformed XML, unsupported TCX extensions, duplicate or invalid timestamps, or files with very large numbers of track points. Re-exporting with a different converter, removing unsupported extensions, or reducing track-point density can help, but simplifying the file may remove detail. Treat FIT as the archival master and use TCX only for the compatibility requirement.