GPX viewer

How to use

1. Drop a GPX file on the box above, choose one, or paste it.
2. The track appears with its elevation profile. Move along the profile, with the mouse or the arrow keys, to see the distance and elevation at each point, marked on the track.
3. Read the distance, ascent, time and speed in the fields below the profile. Switch between kilometres and miles with the units buttons.
4. To see the track on a map, select Show base map. The sentence next to the button says what that sends, and your choice is remembered on this device.

KML and KMZ files open here too. The format is read from the content of the file, so a file with the wrong extension still opens, with a note.

How the numbers are calculated

• Distance adds the straight lines between consecutive points, measured on the Earth’s surface with the haversine formula. A gap between two segments of a recording is not counted.
• Ascent and descent only count a change once it reaches 5 metres from the last counted elevation. GPS elevation wobbles by a few metres even when you stand still, and adding every wobble would inflate the ascent. A slow, steady climb still counts in full.
• Time runs from the first to the last timestamp. Moving time only counts the stretches covered at 1 km/h or faster.
• Average speed is the distance covered while moving, divided by the moving time.

Apps smooth elevation in different ways, so the ascent shown here can differ from the one in the app that recorded the file.

The base map

The track is first drawn on a plain background, and no map service is contacted. When you select Show base map, the map comes from OpenFreeMap, with data from OpenStreetMap. Your browser then asks OpenFreeMap for the map tiles of the area you are looking at, which tells it roughly where the track is, along with your IP address, as any website visit does. The file, its name and its points are never sent.

Limits

• Files up to 100 MB on a computer and 30 MB on a phone or tablet.
• A 10 MB GPX file, about 40,000 points with heart rate and cadence, is read and measured in about 0.2 seconds on a recent laptop.
• On very large tracks, points that would fall within half a pixel of the previous one are left out of the drawing, so the shape stays exact at the size shown.

Your file stays on your device

TrackLoupe reads the file with JavaScript in your browser, in a background worker. No part of the file, its name or its coordinates is sent to a server. To check, open the page, turn on airplane mode, and then open a file: it works the same.

Questions

Can I open a GPX file without installing anything?

Yes. Drop it on this page in any recent browser, on a computer or a phone.

Is my GPX file uploaded?

No. It is read in your browser and stays on your device. The page keeps working with the network off once it has loaded.

Why is the ascent different from my app?

Each app smooths elevation its own way, and some replace GPS elevation with values from an elevation model. This viewer counts a climb once it reaches 5 metres, which removes GPS noise without hiding real climbs.

Can it open routes and waypoints?

Yes. A file with a planned route and no recording shows the route, with its distance and elevation when the points have it. Waypoints appear as points on the track.

What if my file has errors?

The viewer reads everything it can, such as the points of a download that was cut short, and lists what it skipped above the track.