What is grade adjusted pace?
On a hilly run, your pace goes up and down with the terrain even when your effort barely changes. Grade adjusted pace (GAP) converts the pace you actually ran into the flat-ground pace that would have cost the same amount of energy. It lets you compare a hilly trail run with a flat road run, judge whether you pushed too hard on a climb, and set realistic goals for hilly races.
How this calculator works
The calculator uses the energy cost of running measured by Alberto Minetti and colleagues in 2002. They measured runners on a treadmill at gradients from −45 % to +45 % and fitted this curve:
gradient i = elevation change ÷ distance
GAP speed = actual speed × C(i) ÷ C(0)
On flat ground running costs about 3.6 J per kilogram per metre. Going uphill the cost rises steeply; going downhill it falls to a minimum of about 1.8 J/kg/m at around −18 to −20 %, then rises again on very steep descents where you have to brake hard.
Grade adjusted pace chart
The flat-equivalent pace for common running paces on different gradients. Read across from your actual pace.
| Actual pace | -10 % | -6 % | -3 % | +3 % | +6 % | +10 % | +15 % |
|---|---|---|---|---|---|---|---|
| 5:00 /km | 8:22 | 6:55 | 5:53 | 4:16 | 3:39 | 3:01 | 2:26 |
| 5:30 /km | 9:12 | 7:36 | 6:29 | 4:41 | 4:01 | 3:19 | 2:40 |
| 6:00 /km | 10:02 | 8:17 | 7:04 | 5:07 | 4:23 | 3:37 | 2:55 |
| 6:30 /km | 10:53 | 8:59 | 7:39 | 5:32 | 4:45 | 3:55 | 3:09 |
| 7:00 /km | 11:43 | 9:40 | 8:14 | 5:58 | 5:07 | 4:13 | 3:24 |
| 8:00 /km | 13:23 | 11:03 | 9:25 | 6:49 | 5:51 | 4:50 | 3:53 |
| 9:00 /km | 15:03 | 12:26 | 10:36 | 7:40 | 6:35 | 5:26 | 4:22 |
How to use GAP in training and racing
Keep easy runs easy
On hilly routes, check that your GAP — not your raw pace — is in your easy range. Walking steep climbs is completely fine.
Pace hilly races by effort
Aim for roughly even GAP across the race. You will slow on climbs and speed up on descents, but your effort stays steady.
Respect the downhills
Descents look fast on paper but cause more muscle damage. Long downhill sections can make the final kilometres of a race much harder than GAP suggests.
Compare workouts fairly
A tempo run on a rolling course and one on a flat track can be compared through GAP, not raw pace.
Why different apps show different GAP
There is no single official GAP formula. Strava’s current model is based on heart rate data from its athletes, which rates steep downhills more conservatively than laboratory energy measurements. Other platforms use their own models. On gentle grades (−5 % to +5 %) they tend to agree closely; on steep climbs and descents, expect noticeable differences between apps.
Limitations. Minetti’s measurements were made on a treadmill with smooth footing. Trails, mud, rocks, altitude, heat and fatigue all add cost that no GAP formula captures, so use it as a guide rather than a precise measure.
Training indoors? The treadmill incline calculator uses the same model to translate belt speed and incline into outdoor effort. For hot days, combine GAP with the heat pace adjustment.
- Minetti AE, Moia C, Roi GS, Susta D, Ferretti G (2002). Energy cost of walking and running at extreme uphill and downhill slopes. J Appl Physiol 93(3):1039–1046.
Last reviewed: September 2026 · Health disclaimer