Grade Adjusted Pace Calculator

Grade adjusted pace (GAP) is the pace you would run on flat ground for the same energy you spend on a hill. Running uphill costs more energy per mile, so your flat-equivalent pace is faster than the pace on your watch. Running a moderate downhill costs less, so your flat-equivalent pace is slower. GAP lets you compare hilly and flat efforts on an even footing.

It uses the Minetti energy-cost model, a polynomial that gives the metabolic cost of running per kilogram and meter as a function of gradient. The calculator divides the flat cost (3.6 J/kg/m) by the cost at your grade to get an adjustment factor, then multiplies your pace by that factor. For example, a 10% uphill raises the cost to about 5.97 J/kg/m and an adjustment factor near 0.60, so a 10:00 per mile climb adjusts to roughly 6:02 per mile.

Climbing burns more energy for every mile covered, so the slow pace you hold uphill actually reflects a hard effort. The model converts that effort into the faster pace it would produce on flat ground. This is why a steep climb can carry the same effort as a much faster mile on the flat.

Not always. The most economical grade is a moderate downhill of roughly 15% to 20%, where your flat-equivalent pace is at its slowest relative to the hill. On steeper descents the hard braking costs extra energy, so once the grade passes about 20% down the cost climbs again and the slowing effect shrinks. The Minetti model captures this U-shaped cost curve, so very steep downhills are not treated as free speed.

You can enter any grade from -45% (steep downhill) to +45% (steep uphill), the range over which the Minetti model was fitted. Grade is rise over run as a percent, so a road that climbs 6 feet for every 100 feet forward is a 6% grade. Enter downhill grades as negative numbers. Values outside this range return no result because the model is not validated there.

It uses the same Minetti energy-cost curve that popularized grade adjusted pace, so the direction and rough size of the adjustment match. Strava layers in extra smoothing and damping on real GPS data, so exact numbers can differ from a single steady grade. Treat this result as a clean, single-grade estimate of flat-equivalent effort rather than a replacement for a full GPS analysis.