The length of a verified trail on AllTrails is calculated to reflect what you’ll actually experience when you’re out there — not just a rough estimate on a flat map.
To do this, we use two main things: how people really use the trail, and the trail’s ups and downs.
1. We follow the path people actually take
Trails don’t always match the original line that was drawn on an official map.
To account for this, we look at anonymized GPS recordings from millions of AllTrails members. When many recordings overlap, they create a clear picture of where people truly walk, hike, ride, or run.
We average these real-world paths to define the trail route, then measure the distance along that route. This helps avoid inaccuracies from outdated or loosely drawn map lines.
2. We include elevation, not just flat distance
Walking uphill and downhill adds effort — and distance — compared to walking on flat ground.
So instead of measuring a trail as if it were flat, we factor in elevation changes using detailed elevation data. We break the trail into small segments and calculate the true distance of each one, including climbs and descents.
This gives a more realistic total distance than basic map measurements that only look at length on a flat surface.