Open and view a GPX file.

Open a track and the toolbar reports the elevation gain beside the distance and the point count. A file with fewer than two heights has no gain to report, and the row stays empty. The profile at the bottom of the map plots height against distance along the route, so a climb early in the line is not hidden inside a total.

Elevation gain is the sum of the upward parts of that profile. Rises of a metre or less are ignored, which keeps GPS jitter and rounded spot heights out of the number, so the total stays on the low side rather than inflated.

If the file carries no elevation, the map samples terrain data and fills in an estimate for every point, so a flat-looking file can still show a profile. Treat those numbers as estimates — they come from a terrain model, not from a barometer and not from survey data.