VO₂max from Race Time

VO2max Race Predictor

Estimates VO2max from a recent race result and predicts equivalent finish times at other distances. Uses the Riegel formula and Jack Daniels' VDOT system as the basis for calculations.

What is VO2max?

VO2max is the maximum rate at which your body can consume oxygen during exercise, expressed in ml/kg/min. It is the primary indicator of aerobic fitness. Elite marathon runners typically have VO2max values of 65-85 ml/kg/min; recreational runners 40-55.

VO2max norms (adults)

Using race predictions

The predicted times assume equivalent fitness and pacing. Actual performance varies with course profile, weather, fatigue, and pacing strategy. Use predictions as targets, not guarantees. The Riegel formula is most accurate for predictions within two race distance categories of the reference race.

VO2max declines with age, but training slows it

VO2max peaks in the mid-20s and declines by approximately 1% per year after age 25 in sedentary individuals. For trained endurance athletes, the decline is slower, roughly 0.5% per year, because consistent aerobic training preserves cardiovascular capacity. This means a 50-year-old recreational runner who has trained steadily since age 30 may have a similar VO2max to a sedentary 35-year-old. Masters runners in the UK (40+) can track this decline through parkrun age-grading: a declining age-graded score signals fitness loss; a stable or rising score signals maintenance or improvement.

Eluid Kipchoge and the limits of VO2max

Eliud Kipchoge, the first person to run a sub-2-hour marathon (1:59:40, Vienna, 2019, not ratified as a world record due to pacing setup), has a VO2max measured at approximately 85 ml/kg/min. However, what distinguishes elite marathon runners is not just high VO2max but also exceptional running economy (less oxygen used per km at a given pace) and a very high lactate threshold (ability to sustain a high percentage of VO2max for hours). A recreational runner with a VO2max of 50 ml/kg/min can improve marathon time substantially by improving economy and threshold, without changing VO2max at all.

Using a recent parkrun or 10K as your reference

For UK runners, the easiest way to use this tool is to enter a recent parkrun (5K) or 10K time. parkrun times are free, consistent, and measured on accurate courses, making them ideal reference races. Enter your most recent parkrun time to get an estimated VDOT and predicted times for half marathon and marathon. Note that parkrun courses vary in difficulty, Bushy Park and Dulwich are fast, while hilly courses like Cannon Hill or Belair will give slower times that underestimate flat-road fitness.