Pace at a Percentage of MAS Calculator
Written by Thierno Sadou Diallo, formula verified per our methodology • Last checked on 9/10/2026
Pace at a percentage of MAS is calculated with target speed = MAS × percentage ÷ 100, then pace = 3600 ÷ target speed. At 85% of a 16 km/h MAS, target speed is 13.6 km/h, a pace of 4:25 per km.
Explanation
Maximal aerobic speed (MAS) is the speed at which a runner reaches their maximum oxygen uptake: it's the reference from which most running training plans define their working paces, expressed as a percentage of MAS. This calculator converts a percentage of MAS into a concrete pace (min/km) and speed (km/h), from a MAS you already know — measured on a field test via our MAS calculator (half-Cooper test), or given by a coach. It deliberately sets no target percentage by session type: the usual correspondences (easy endurance often run around 65-75% of MAS, threshold work around 80-90%, short intervals at 100-110%) vary by training method and runner level, and are better set with a coach than applied mechanically. The calculation assumes a strictly proportional relationship between percentage of MAS and speed, which remains a useful approximation across the range of common training paces, but departs from physiological reality at the extremes (at a very low percentage, running gives way to walking; above 100%, the speed can only be held for a few minutes). To calculate the reverse — the pace to hold for a target time over a given distance — see our goal pace calculator.
Example: a 16 km/h MAS, pace at 85%
Inputs
MAS: 16 km/h. Target percentage of MAS: 85%.
Calculation
Target speed = 16 × 85 ÷ 100 = 13.6 km/h. Pace = 3600 ÷ 13.6 ≈ 264.7 s/km, rounded to 265 s, or 4:25 per km.
Result
At 85% of a 16 km/h MAS, you need to run at 13.6 km/h, a pace of 4:25 per km.
Frequently asked questions
At what percentage of MAS should easy endurance be run?
Commonly cited benchmarks put easy endurance (the slow running that makes up most of training volume) around 65 to 75% of MAS, but these values vary by method and runner level. This calculator deliberately sets no target value: enter the percentage recommended by your training plan or coach to get the corresponding pace.
Why is the relationship between percentage of MAS and speed assumed proportional?
It's a simplification: across the range of common training paces (about 60 to 105% of MAS), running speed is approximately proportional to the percentage of MAS, which makes the direct calculation reliable enough. At the extremes, this relationship departs from reality (walking replaces running at very low pace, and a speed above 100% of MAS can only be held briefly), but these zones fall outside the usual use of this calculation.
How do I get my MAS if I don't know it?
The half-Cooper test (maximum distance covered in 6 minutes of running, on a track or measured flat course) is one of the simplest protocols: our MAS calculator directly converts that distance into MAS. Other tests exist (VAMEVAL, Léger shuttle test), more precise but requiring equipment or specific organization.