VO2max calculator
Estimate VO2max from a recent race, a 12-minute run, or a maximal bike effort. Use it alongside pace and power. It is a field estimate, not a lab test.
Use a recent race or time trial you ran as hard as you could hold. The estimate uses Jack Daniels’ equations, the same idea as the event run pace prediction calculator.
Enter maximal aerobic power: the highest power from a ramp test, or a maximal effort of about 4 to 6 minutes. Do not enter FTP or a 20-minute test. Those sit below VO2max, and the estimate will come out low.
Enter the distance covered in 12 minutes, on flat ground, paced as evenly as you could. The estimate uses Cooper’s equation.
How the estimate is made
Run race
Jack Daniels’ equations turn the pace of a hard race or time trial into a VO2max-style score, often called VDOT. It sits close to a lab result for many runners. It also reflects running economy, so the two numbers are not the same thing. For training paces from that race, use the event run pace prediction calculator.
Bike power
The ACSM leg-ergometer equation estimates how much oxygen it costs to hold a given power. Use it with maximal aerobic power: a ramp test, or a maximal effort of about 4 to 6 minutes. FTP and 20-minute tests sit below VO2max, so they come out low. The equation assumes a typical efficiency, so a more economical rider reads a little high.
12-minute run
Cooper’s test estimates VO2max from the distance covered in 12 minutes of even, maximal running on the flat. Heat, hills and going out too hard all move the number. It is less precise for runners who are much older, or much less trained, than the group the test was built on.
Retest the same way when you want to compare. A different course, a different position on the bike, or a day you were not ready for will move the result by more than a real change in fitness. A laboratory test with gas analysis is the reference.
What is VO2max?
VO2max is the most oxygen your body can take in and use during hard exercise. It is usually written in millilitres per kilogram per minute. A higher figure means a higher aerobic ceiling.
It is one part of performance. Two athletes with the same VO2max can race very differently, because threshold, economy and durability all sit on top of that ceiling. A laboratory test with a mask is the reference. This page estimates it from a race, a 12-minute run, or a maximal bike effort.
How to train it
The work that moves VO2max is hard, and it has to be repeatable. Use efforts you could hold for about 3 to 8 minutes, several times, with enough recovery that the next rep is the same pace or power. If the reps slide, the recovery was too short or the session was too big.
On the run, that is often around 3 km to 5 km effort. A session might be 5 × 3 minutes, or 4 × 5 minutes, with an easy jog between. On the bike, use a power close to a maximal 4 to 6 minute effort. FTP sits below this, so a session at FTP will not reach the same place.
Keep these sessions in a block of a few weeks, with one or two of them in a week for most people. The rest of the week is easier riding and running. That is where you recover, and where you keep the endurance that lets you do the hard work properly.
The calculators are a starting point. Coaching is where the number turns into the sessions.
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