What this calculator does
Most VO2 max estimates come from a dedicated fitness test: a 12-minute maximal run, or a fixed treadmill protocol. This VO2 max calculator for runners works differently, estimating VO2 max directly from a recent race result, since a race is a maximal or near-maximal effort most runners already have on record.
It uses the Jack Daniels and Jimmy Gilbert formula, developed specifically for distance runners, which converts race pace and duration into an estimated VO2 max and the percentage of that VO2 max sustained during the effort.
The formula
Race velocity is distance divided by time, in metres per minute. That velocity feeds a formula for oxygen cost, which is then divided by an estimate of what percentage of VO2 max a runner can sustain for that duration, since nobody races at 100% of VO2 max, even in a short race. Longer races are run at a lower percentage of VO2 max than shorter ones, and the formula accounts for that.
| Term | Meaning |
|---|---|
| VO2 max | Maximum rate of oxygen the body can use during intense exercise, in millilitres per kilogram of body weight per minute. |
| Race velocity | Race distance divided by finish time, the average speed sustained across the whole effort. |
| % of VO2 max sustained | The estimated share of maximum oxygen uptake a runner holds for the full duration of that specific race distance. |
The inputs explained
| Field | What to enter |
|---|---|
| Race distance (km) | The distance of a recent race, at close to maximal effort. Any distance from a 1-mile time trial to a marathon works. |
| Finish time: minutes | Finish time, minutes component. |
| Finish time: seconds | Finish time, seconds component. |
When to use it
Estimating fitness without a lab test
A recent race result gives a reasonable VO2 max estimate without needing a treadmill test or a maximal 12-minute time trial.
Tracking fitness changes between races
Running the same race distance again some months later and comparing the estimated VO2 max shows whether aerobic fitness has genuinely improved, separate from just getting faster at pacing.
Predicting a finish time at a different distance instead
If the goal is a race-time prediction rather than a fitness number, the race time predictor uses the same kind of input to estimate a finish time at a new distance directly.
Worked examples
Every figure in the tables below is produced by this page’s own calculator at build time, so the numbers and the tool always agree. Select any row to load that scenario.
Estimated VO2 max across a range of 5 km finish times
A fixed 5 km distance, across a range of finish times.
| Finish time (minutes) | Estimated VO2 max | Race pace used |
|---|---|---|
| 18 min | 56.3 ml/kg/min | 3:36 min/km |
| 20 min | 49.8 ml/kg/min | 4:00 min/km |
| 22 min | 44.5 ml/kg/min | 4:24 min/km |
| 25 min | 38.3 ml/kg/min | 5:00 min/km |
| 28 min | 33.5 ml/kg/min | 5:36 min/km |
| 30 min | 30.8 ml/kg/min | 6:00 min/km |
Questions
How accurate is a VO2 max calculated from a race time?
It is a well-tested estimate for distance runners, built on the same relationship used in the Daniels-Gilbert VDOT tables, but it is still an estimate. A lab test with gas analysis remains the direct measurement.
Does the race distance matter for accuracy?
Any distance run at a genuinely hard, close-to-maximal effort works reasonably well, from a mile time trial up to a marathon. A very easy long run will underestimate VO2 max, since the effort level was never close to maximal.
How is this different from the Cooper test VO2 max calculator?
The Cooper test calculator needs a fixed 12-minute maximal run. This calculator works from whatever race result you already have, at whatever distance that race happened to be.
What is a good VO2 max for a runner?
It varies enormously by age, sex and training background, so there is no single number to aim for. Tracking your own estimate over successive races is more useful than comparing against a generic benchmark.
For a VO2 max estimate from a fixed 12-minute test instead of a race result, see the VO2 max calculator. For a treadmill-protocol version, see the Bruce protocol VO2max calculator.