Tool · Physiology
VO₂max calculator for runners
Estimate your maximal oxygen uptake from a recent race, the 12-minute Cooper test or your maximal aerobic speed. You also get your MAS, your pace at MAS and your VDOT, calculated with the Jack Daniels method that powers RunMorph plans.
Estimate from your race time (Jack Daniels’ VDOT model). Raw VO₂max (MAS × 3.5) is your theoretical maximal oxygen uptake; VDOT is a performance index, deliberately lower, because it factors in your running economy. These values remain estimates and are no substitute for a lab stress test.
How to estimate your VO₂max
VO₂max is the maximum amount of oxygen your body can use during exercise, expressed in ml/kg/min. It’s one of the markers of aerobic potential. Only a lab can measure it precisely (mask and gas analysis), but three field methods give a solid estimate.
1. From a race time (VDOT method, the most reliable)
Start from a recent performance over a known distance. Jack Daniels’ VDOT model derives a performance index (VDOT) and the matching maximal aerobic speed (MAS), which gives raw VO₂max = MAS (km/h) × 3.5. It’s the calculator’s default method. Example: a 10K in 50:00 gives a MAS of about 8.1 mph (13.1 km/h), so a raw VO₂max of 13.1 × 3.5 ≈ 46 ml/kg/min.
2. The Cooper test (12 minutes)
Run all-out for 12 minutes and measure the distance covered. With the distance in miles:
Example: 1.74 miles (2,800 m) in 12 minutes gives (35.97 × 1.74) - 11.29 ≈ 51 ml/kg/min, for a MAS of about 51 ÷ 3.5 ≈ 14.6 km/h (9.1 mph). With the distance in meters, the formula becomes (distance - 504.9) ÷ 44.73.
3. From your MAS
If you already know your MAS (half-Cooper test, stage test…), the conversion is direct:
Example: a MAS of 9.9 mph (16 km/h) matches a raw VO₂max of 16 × 3.5 = 56 ml/kg/min.
Raw VO₂max or VDOT? Raw VO₂max (MAS × 3.5) is a theoretical physiological value. VDOT is a performance index that factors in your running economy: two runners with the same VO₂max but different economy won’t run at the same speed. That’s why VDOT usually sits a little below raw VO₂max, and why it predicts your race times better. The pace for a given speed is pace (min/mi) = 60 ÷ speed (mph).
MAS chart: matching VO₂max
How maximal aerobic speed translates into estimated raw VO₂max (MAS in km/h × 3.5), with your running pace at MAS. A handy benchmark to link your speed on the road to your aerobic potential.
| MAS | Pace at MAS | Raw VO₂max (MAS × 3.5) |
|---|---|---|
| 7.5 mph | 8:00 /mi | ≈ 42 ml/kg/min |
| 8 mph | 7:30 /mi | ≈ 45 ml/kg/min |
| 8.5 mph | 7:04 /mi | ≈ 48 ml/kg/min |
| 9 mph | 6:40 /mi | ≈ 51 ml/kg/min |
| 9.5 mph | 6:19 /mi | ≈ 54 ml/kg/min |
| 10 mph | 6:00 /mi | ≈ 56 ml/kg/min |
| 10.5 mph | 5:43 /mi | ≈ 59 ml/kg/min |
| 11 mph | 5:27 /mi | ≈ 62 ml/kg/min |
| 11.5 mph | 5:13 /mi | ≈ 65 ml/kg/min |
| 12 mph | 5:00 /mi | ≈ 68 ml/kg/min |
These values are estimates based on VO₂max ≈ MAS (km/h) × 3.5. The calculator above refines the result with the VDOT method when you start from an actual race time.
Frequently asked questions
What is VO₂max in running?
VO₂max is the maximum amount of oxygen your body can use per minute during intense exercise. It’s expressed in milliliters of oxygen per kilogram of body weight per minute (ml/kg/min). The higher it is, the greater your aerobic potential. Recreational runners often sit between 40 and 55 ml/kg/min; elites go above 70.
How can I estimate my VO₂max without a lab test?
Three accessible methods: (1) from a recent race time (5K, 10K, half…), using Jack Daniels’ VDOT index, the most reliable because it reflects a real performance; (2) with the Cooper test: run all-out for 12 minutes, and VO₂max = (35.97 × miles) - 11.29; (3) from your maximal aerobic speed, with VO₂max ≈ MAS (km/h) × 3.5. This calculator offers all three.
What’s the difference between VO₂max and MAS?
VO₂max is an oxygen uptake (in ml/kg/min); MAS, or maximal aerobic speed, is the running speed at which you reach that VO₂max. You go roughly from one to the other with VO₂max ≈ MAS (km/h) × 3.5. In other words, MAS turns VO₂max into a real-world speed you can use straight away to set your paces.
Why is VDOT lower than raw VO₂max?
Jack Daniels’ VDOT isn’t a measured VO₂max: it’s a performance index that factors in your running economy (the oxygen you actually spend to run at a given speed). Two runners can share the same raw VO₂max yet have different VDOTs. That’s why VDOT is usually a little lower than the VO₂max estimated from MAS × 3.5.
Is the Cooper test a reliable way to estimate VO₂max?
The Cooper test (12 minutes at maximal effort) gives a good estimate for a trained runner who can hold a steady, truly maximal pace for the whole duration. Its accuracy depends heavily on how honest the effort is, the surface (ideally a flat track) and the weather. For a more stable benchmark, an estimate from a race time is still the better choice.
Turn your VO₂max into a training plan
RunMorph starts from your maximal aerobic speed and your VDOT to work out your 7 training paces and build a session-by-session plan, periodized all the way to race day.
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