Grade-Adjusted Pace Calculator
Enter a pace and a grade. Choose whether you ran that pace on the grade and want the flat-equivalent effort, or you have a flat target pace and want the matching pace on the grade.
Mode
Flat-equivalent pace
At 5% grade.
Pace by grade, same effort
| Grade | Pace |
|---|---|
| -10% | 3:33 /km |
| -5% | 3:37 /km |
| 0% | 4:05 /km |
| +5% | 5:00 /km |
| +10% | 6:20 /km |
This estimate uses a generic formula. Connect your Strava/Whoop/Garmin data for a version personalised to your actual training.
Get early accessWhy grade changes the effort behind a pace
The same clock pace means something different on a hill than on the flat. Climbing at 5:00 /km is a much harder effort than running 5:00 /km on level ground, and descending at 5:00 /km is easier, up to a point: beyond a certain downhill steepness, braking and footing eat back the free speed and the effort climbs again. Grade-adjusted pace converts a pace on a slope into the flat pace that represents the same physiological effort, so you can compare hilly segments, hilly races, and flat training paces on a level playing field.
How it is calculated
This calculator uses the quadratic grade-pace model from the open-source Ultrapacer planner: factor = 0.0021 × grade² + 0.034 × grade + 1, where grade is a percentage and factor is how much slower (factor > 1) or faster (factor < 1) the same effort reads on that grade compared to flat. Your pace is multiplied by that factor, or divided out of it, depending on which direction you are converting. The small table shows the same flat-equivalent pace projected onto a handful of common grades.
How to use the result
Use the flat-equivalent pace to judge effort on a hilly training route or race segment against a flat goal pace, or to pace a known hill without blowing up early. The model is fit to road and trail grades from about −22% to +16%; it still returns a number outside that range, but treat it as a rougher estimate the steeper the grade gets.
Sources and limitations: see our methodology.
Worked example
Take a runner holding 5:00 /km on a 5% uphill grade.
The empirical factor at +5% is about 1.22, so the flat-equivalent pace is 4:05 /km. In other words, grinding out 5:00 /km uphill is roughly the same effort as running 4:05 /km on level ground, almost a minute per kilometre faster. That is the gap a flat goal pace does not account for on a hilly course.
FAQ
What is grade-adjusted pace?
Grade-adjusted pace (GAP) is the flat-ground pace that represents the same effort as a pace actually run on a slope. Climbing takes more effort than the same clock pace on flat ground, and descending takes less, so GAP converts a hilly pace into its flat equivalent for a fair comparison.
How do I convert a hilly pace to a flat pace?
Enter the pace you actually ran and the grade of that section, in "Pace on a grade → flat pace" mode. The calculator multiplies your pace by the grade's pace factor to give the flat-equivalent effort.
Does grade-adjusted pace account for downhill speed gains?
Yes, but conservatively. This calculator uses the empirical quadratic model from the open-source Ultrapacer planner rather than the Minetti metabolic curve, because Minetti overstates how much free speed a runner can actually bank on a descent: braking, footing, and quad fatigue eat into the metabolic saving. The empirical model's fastest effective grade is around −8%, matching how runners actually pace descents rather than the metabolic optimum.
What's the difference between the Minetti and empirical grade models?
Minetti et al. (2002) measured the metabolic energy cost of running on a treadmill from −45% to +45% grade: it is the standard peer-reviewed reference for how much energy running on a slope costs. The empirical model used here is fit to match observed pacing behaviour instead, so it under-rewards downhill running compared to Minetti on purpose. See the methodology page for the full comparison.
How accurate is grade-adjusted pace for trail running?
Reasonably accurate for rolling and moderate trail grades, within roughly −22% to +16% where the empirical model is fit. Very steep sustained climbs or descents, loose or technical footing, and altitude all add effort this calculator does not model, so treat the number as a pacing guide, not a guarantee.
Why does uphill running count as a faster flat pace?
Because the conversion runs in both directions. A hard uphill effort at a slow clock pace corresponds to a faster flat pace at the same effort, which is exactly why grade-adjusted pace lets you compare a hilly split to a flat one on equal terms.