Altitude Pace Adjustment Calculator

About this calculator

Running pace slows at higher altitude mainly because thinner air holds less oxygen per breath, reducing the amount of oxygen the blood can pick up and deliver to working muscles at any given effort — the same submaximal pace that felt moderate at sea level demands a higher percentage of VO2max once you're above roughly 1,500 meters (about 5,000 feet), and the effect grows with elevation. The relationship is commonly approximated as a percentage pace slowdown per unit of elevation gained above a threshold altitude, though individual acclimatization changes how much the effect fades over days to weeks at altitude.

Runners racing or training somewhere higher than they live use this kind of adjustment to set a realistic pace goal instead of chasing sea-level splits that simply aren't achievable at altitude, and travelling athletes use it to avoid starting a race or workout too aggressively in thin air. It's also useful in reverse, for runners who train at altitude and want to estimate how much faster they might run once they return to sea level.

This calculator takes your sea-level pace and the altitude you'll be running at, and returns your estimated adjusted pace at that elevation.