Grade-adjusted pace and climb calculator

What grade-adjusted pace is

Grade-adjusted pace (GAP) estimates the flat-ground pace that would cost the same effort as the pace you actually ran on a slope. Running uphill takes more energy per meter than running on the level, so the GAP for a climb is faster than the pace on your watch. Gentle descents cost less, so their GAP is slower.

The version here uses the running cost regression from Minetti et al. (2002), which measured the metabolic cost of running on treadmill grades from 45% downhill to 45% uphill. That study found level running costs about 3.6 joules per kilogram per meter, rising more than fivefold at the steepest uphill grades, with the cheapest running of all on a roughly 20% descent. The calculator converts your pace with those cost ratios and refuses to extrapolate beyond the grades the study measured.

A worked example, from the hill our own mock data is built on: a 640 m repeat gaining 54 m is an 8.4% grade. Run it in 3:12 and your watch shows 5:00 per kilometer. The energy model prices that grade at roughly 1.5 times the cost of flat ground, so the grade-adjusted pace is about 3:15 per kilometer. The watch says you jogged; the hill says you flew.

What the number is good for

GAP is at its best as a sanity check. It tells you that a slow split on a climb was honest work, it lets you compare a hilly run against a flat one in rough terms, and it makes hill repeats legible: a rep at 5:00 per kilometer up 8.4% is a very different effort from the same pace on the flat, and the effort factor says by how much.

What it cannot know

Every GAP model, including this one, adjusts for gradient and nothing else. A treadmill regression has never met roots, rocks, sand, mud or 30 degree heat, and it assumes an average runner when uphill economy differs meaningfully from person to person. Even Strava's own documentation notes that GAP does not account for the technical difficulty or condition of the terrain. Treat the output as a well-informed estimate, not a verdict. We wrote more about where GAP breaks down on trails in our field note on grade-adjusted pace.

Better than adjusting: comparing like with like

The most honest use of a hilly segment is not converting it to a flat equivalent at all. It is comparing it against your own previous times on the same ground, where the grade, footing and turns are identical every visit. If that idea appeals, start with how to measure trail running progress and why kilometer splits lie on trails.