Grade-Adjusted Pace (GAP) Calculator

Grade-adjusted pace (GAP) answers the question: if I run 8:00/km on a 15% climb, how hard am I actually working? GAP normalises your pace to what it would be on flat ground at the same physiological effort — making it possible to compare efforts across different terrain.

The Minetti cost curve is non-linear. Running costs increase sharply on uphills — 15% grade costs about 2.2× more energy than flat — and mildly decrease on gentle downhills before rising again at steep descents. This means that a runner "slowing down" on a climb isn't necessarily working less hard; they may be working substantially harder.

Eccentric braking cost: On steep descents, the quadriceps absorb kinetic energy through eccentric contractions. At around −20% and steeper, this braking cost exceeds the gravitational assist — the descent actually costs more energy than a mild gradient. The gradient table shows this non-linear behaviour clearly.

Power hiking: Above approximately 15% grade, running becomes mechanically inefficient compared to power hiking (Koop, 2021). The gradient table highlights these rows so you can build race strategies that incorporate intentional hiking sections at optimal gradient thresholds.

How to use this for race pacing: Choose a target flat-equivalent effort (e.g. 5:00/km). Read off the actual pace you should run at each gradient on your course. This gives you a pacing plan that maintains consistent effort rather than constant pace — the physiologically correct approach for hilly trail races.

Minetti AE et al. (2002). Energy cost of walking and running at extreme uphill and downhill slopes. J Appl Physiol. 93(3):1039–46. Koop J. (2021). Training Essentials for Ultrarunning. VeloPress.