Adjusting one climb at a time is tedious — the app grade-adjusts every run automatically so hilly efforts get the credit they deserve: App Store · Google Play
What is grade-adjusted pace?
Grade-adjusted pace (GAP) answers a simple question: how fast would I have been running on the flat for the same effort? Because climbing costs so much extra energy, a pace that looks slow on a hill can be a genuinely fast effort. GAP converts your hill pace into that flat-ground equivalent, so you can compare a hilly run with a flat one fairly.
Switch the mode to run the calculation the other way: enter your normal flat pace and a grade, and it tells you the (slower) pace to actually run on that incline to keep the effort the same — the key to not blowing up on climbs.
How much does a grade change the effort?
This calculator uses the energy cost of running on a gradient. The effect is bigger than most runners expect, and it is what your GPS watch's "GAP" figure is doing under the hood. Here is how each grade changes the effort and what a 5:00/km flat effort becomes on that slope — the values this calculator produces.
| Grade | Effort vs flat | 5:00/km flat effort → actual pace |
|---|---|---|
| −5% (down) | −24% | 3:49 /km |
| −2% (down) | −10% | 4:29 /km |
| 0% (flat) | 0% | 5:00 /km |
| +2% (up) | +11% | 5:34 /km |
| +5% (up) | +30% | 6:30 /km |
| +8% (up) | +51% | 7:33 /km |
| +10% (up) | +66% | 8:17 /km |
How to use GAP in training
- Run hills by effort: use "flat effort → hill pace" to find the slower pace to hold on a climb so an easy run stays easy.
- Compare hilly and flat runs: a 6:30/km effort up a 5% hill is really a 5:00/km flat run — credit yourself accordingly.
- Pace hilly races: aim for an even effort (even GAP), not an even pace, and you will finish far stronger.
- Downhill caution: the model rewards gentle downhills, but steep descents pound your quads — do not chase the fast GAP down a steep hill.
Pace every run by effort, not just the clock
The Running Genie factors terrain and effort into your training, so hilly and flat runs both count the right amount toward your goal.
Frequently asked questions
What is grade-adjusted pace (GAP)?
Grade-adjusted pace is the flat-ground pace that would take the same effort as the pace you actually ran on a hill. Because running uphill costs more energy, a slow uphill pace can be equivalent to a much faster flat pace. GAP lets you compare hilly and flat runs on a level footing.
How is grade-adjusted pace calculated?
This calculator uses the energy cost of running on a gradient (Minetti et al., 2002). It works out how much more or less energy a grade costs compared with flat ground, then adjusts your pace by that ratio. A 5% incline is roughly 30% harder than flat, so a 6:30/km climb is about a 5:00/km flat effort.
Why is my uphill pace so much slower than flat?
Lifting your body weight against gravity adds a large energy cost. Even a modest 2% grade is about 11% harder than flat at the same speed, and a 10% grade is well over 60% harder. That is why your pace drops sharply on climbs even though your effort feels the same or higher.
Does running downhill count as easier?
Gentle downhills do reduce the energy cost, so your grade-adjusted pace is slower than your actual downhill pace. But very steep descents get harder again because of braking and eccentric muscle load, which this energy-cost model does not fully capture — treat steep downhill GAP as an underestimate of difficulty.
How do I use GAP in training?
Use it to run hilly routes by effort rather than pace. Switch this calculator to "flat effort → hill pace", enter your flat easy or workout pace, and it tells you the slower pace to hold on the climb to keep the effort right — so you do not blow up charging up hills.
Related running calculators
Conquer the hills
Download The Running Genie for a plan that paces your runs by effort and builds the strength to run hills well.