Running VO2max calculator: your VDOT and equivalent times
This calculator estimates your VO2max from a race time, using the VDOT of Jack Daniels and Jimmy Gilbert (1979). It also gives your equivalent times for 5K, 10K, half marathon and marathon, at the same fitness level.
Fill in the fields to see the result.
How to use it
- Choose the distance of a recent race you ran all out.
- Enter your time.
- Read your VDOT, your estimated VO2max in ml/kg/min.
- Look at your equivalent times for the other distances.
The method
Daniels and Gilbert linked two things measured in the lab. First, the oxygen cost of a running speed: the faster you run, the more oxygen you use. Second, the share of your VO2max you can hold depending on how long the effort lasts: almost 100% for an effort of about ten minutes, much less for a marathon. By dividing the oxygen your speed requires by the share you can hold for that duration, you get the VDOT: the “effective” VO2max your performance implies.
For equivalent times, the calculation works the other way: it looks for the time that gives the same VDOT over each distance. These tables were published in Oxygen Power (1979), then included in Daniels' Running Formula, one of the most widely used training books in Europe and the United States.
An example
You run 10 km in 50:00: your VDOT is about 40 ml/kg/min. The same fitness level gives 24:06 for 5K, 1:50:52 for a half marathon and 3:49:34 for a marathon. A 5K in 20:00 gives a VDOT of 49.8, which means 41:28 for 10K and 1:31:50 for a half.
Limitations
VDOT isn't your lab VO2max: it blends your VO2max and your running economy. Two runners with the same measured VO2max can have different VDOTs. The equivalent times assume you're just as well prepared for each distance: without long runs, your real marathon will often be slower than predicted, as with the Riegel formula (Vickers and Vertosick, 2016). A race on a hilly course, in strong heat or poorly paced underestimates your VDOT. For a real VO2max measurement, you need an exercise test with gas analysis, with a sports doctor or in a lab.
Frequently asked questions
How can you know your VO2max without a lab test?
A recent race run all out gives a good estimate with VDOT. Your watch also offers one, calculated from your heart rate and your pace.
What's a good VO2max for a runner?
It depends a lot on age, sex and training. The most useful thing is to follow your own progress from one race to the next.
What's the difference between VDOT and VO2max?
VO2max is measured in a lab. VDOT is the VO2max your performance implies: it also takes your running economy into account.
Why does my watch give a different VO2max?
It uses its own method, often based on heart rate. VDOT only starts from your race time, which is why they can differ by a few points.
Sources
- Daniels, J. and Gilbert, J. (1979). Oxygen Power: Performance Tables for Distance Runners. Self-published.
- Daniels, J. (2022). Daniels' Running Formula, 4th ed. Human Kinetics.
- Vickers, A. J. and Vertosick, E. A. (2016). An empirical study of race times in recreational endurance runners. BMC Sports Science, Medicine and Rehabilitation, 8, 26.
What if ELYO worked it out for you?
ELYO reads the workouts from your watch and tracks your fitness from your real data, not from a single race. It works out your paces and your training load, then adjusts your plan week by week.