Grade adjusted pace calculator

Why raw pace is misleading on hills

Running the same pace uphill and on flat ground takes very different amounts of effort — a 5:00/km pace on a steep climb might be nearly race effort, while the same pace on flat ground is comfortable. Grade adjusted pace (GAP) removes the terrain from the equation by converting your actual pace at a given gradient into the pace you would run for the same effort on flat ground.

This calculator uses the Minetti energy cost of running model (Minetti et al., 2002) — the same physiology-based approach used by Strava and most GPS running watches. It is validated for gradients between -45% and +45%, and captures a key nuance: gentle downhills (roughly -10% to -20%) are the most economical grade to run, cheaper than flat ground, while very steep descents cost more again due to the braking effort required.

To plan pacing for a flat race from a hilly training run, calculate your GAP here, then use the race predictor or target pace calculator with the flat-equivalent result.

Frequently asked questions

What is grade adjusted pace (GAP)?

Grade adjusted pace (GAP) converts a pace run on a hill into the equivalent pace you would run on flat ground for the same effort. It accounts for the fact that running uphill costs more energy per kilometre, while gentle downhills cost less — so comparing raw paces across varied terrain is misleading.

How is grade adjusted pace calculated?

This calculator uses the Minetti energy cost of running model (Minetti et al., 2002), a polynomial equation validated for gradients between -45% and +45% that estimates the metabolic cost of running at any slope relative to flat ground. Your actual pace is divided by this cost ratio to get the flat-equivalent pace.

Why does downhill running sometimes get a slower grade adjusted pace?

Gentle downhills (roughly -10% to -20%) are the most economical gradient to run — cheaper than flat ground. On very steep downhills, the metabolic cost of braking your stride starts to rise again. Either way, the same downhill pace generally reflects less effort than it would on the flat, so its GAP is slower than the raw pace.

Is grade adjusted pace the same as the GAP shown on Strava or GPS watches?

Most platforms, including Strava and many GPS watches, use the same Minetti-based model or a close variant, so results should be very similar. Small differences can occur due to elevation smoothing, GPS/barometer accuracy, and rounding, but the underlying physiology-based approach is the same.