VO₂ Max Estimator
Estimate your aerobic capacity from any race result and see how your fitness compares to other runners.
VO₂ max is estimated using the Daniels-Gilbert oxygen cost equations, which calculate the oxygen demand of running at a given velocity and the fraction of VO₂ max sustained during the race. This method has been validated against lab-measured VO₂ max in trained runners and is the same model used in commercial fitness trackers.
Fitness classifications use ACSM age- and gender-adjusted norms (American College of Sports Medicine, Guidelines for Exercise Testing and Prescription). VO₂ max naturally declines ~10% per decade after 25, so age-group comparisons give a more meaningful picture of your fitness than raw numbers alone.
The estimate back-calculates VO₂ max from your race by assuming a fixed running economy — a fixed oxygen cost for every pace. But economy varies 20–30% between runners. Two people with the same 5K time but different economy have genuinely different VO₂ max, and the formula hands them the same number. The “fraction of VO₂ max you can sustain” is likewise a fixed average standing in for a variable that’s personal and trainable.
Race performance is the product of three things — VO₂ max, lactate threshold, and running economy — and one race time can’t separate them. So this number is really a performance index, not a measured ceiling: it can rise when your economy or threshold improves with no change in true VO₂ max. That’s also why lab VO₂ max predicts race times poorly between individuals.
Vertical tracks those three drivers separately across your training instead of collapsing them into one back-calculated figure, and reads the trend over many sessions — so a single windy or badly-paced race doesn’t move your fitness picture.
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