Trail ↔ road effort calculator
On the trail, distance alone is misleading: 25 km with 1,200 m of climbing is a very different effort from 25 km on the flat. This calculator estimates the flat-road effort equivalent of a trail run using a widely-used coaching heuristic — roughly 100 m of vertical gain costs about the same effort as 1 extra km on the flat. Use it to size your trail sessions against familiar road distances.
Effort equivalent
37.0 km — flat-road equivalent
Heuristic: 100 m climb ≈ 1 km flat effort. Real trail times vary with terrain, descents and fatigue.
How it works
Effort-equivalent flat distance = trail distance (km) + elevation gain (m) ÷ 100. Enter your flat pace too and it estimates a ballpark trail time. It's a planning heuristic, not a guarantee — technical terrain, descents, altitude and fatigue all shift real times.
Frequently asked questions
How do you convert elevation gain to distance?
A common coaching rule: every 100 m of climbing adds roughly 1 km of flat-effort distance. So 25 km with 1,200 m of climbing feels like about 37 km on the flat.
Is this accurate for technical trails?
It's a rough planning estimate. Very technical terrain, steep descents, mud, altitude and night running all slow you further than the formula suggests. Treat it as a floor, not a finish-time prediction.
Why train by effort instead of pace on trail?
Because pace is meaningless across changing grades — your pace collapses uphill at the same effort. Training and racing by heart rate or perceived effort (and power-hiking climbs) is how trail runners pace correctly.