Estimate your VO2 max (cardiorespiratory fitness) using the Cooper 12-minute run, Rockport 1-mile walk, or heart rate ratio method. Metric and imperial supported.
VO2 max is the maximum amount of oxygen your body can use during intense exercise, measured in millilitres of oxygen per kilogram of body weight per minute (mL/kg/min). It's the standard scientific measure of cardiorespiratory fitness. This calculator estimates it from a field test you can do without a lab — choose the Cooper 12-minute run, the Rockport 1-mile walk, or a resting/max heart rate ratio — using peer-reviewed prediction equations. Field-test estimates are less precise than a laboratory gas-exchange test, but they're a reasonable, free way to track your aerobic fitness over time.
Descriptive population reference, not a medical or diagnostic scale. Tick mark shows the 50th percentile for your age and sex.
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VO2 max (V̇O2max) is the maximum rate at which your body can take up and use oxygen during intense, whole-body exercise. It's measured in millilitres of oxygen per kilogram of body weight per minute (mL/kg/min) and is widely used by exercise physiologists as the standard indicator of cardiorespiratory (aerobic) fitness. A higher VO2 max generally means your heart, lungs and muscles are more efficient at delivering and using oxygen during sustained effort.
VO2 max is directly measured in a lab using a cardiopulmonary exercise test (CPX) — typically running or cycling to voluntary exhaustion while breathing through a mask that analyses oxygen and carbon dioxide. Because that requires specialised equipment, several field tests have been developed to estimate VO2 max from things you can measure yourself: distance covered in a fixed time, time taken to cover a fixed distance, or your heart rate response. This calculator uses three of the more established field-test equations.
Each method below uses a different, independently validated regression equation. None of them measure VO2 max directly — they estimate it from a field test, so all carry a margin of error larger than a lab test.
Developed by Kenneth Cooper and published in JAMA in 1968, this equation was derived from 115 US Air Force personnel who ran as far as possible in 12 minutes, compared against treadmill-measured VO2 max (correlation r = 0.90). Run as far as you can in exactly 12 minutes, then enter your distance. Walking instead of running will typically cover less distance and wasn't the basis for this equation — if you specifically need a validated walking test, use the Rockport 1-mile walk method below instead.
Published by Kline and colleagues in Medicine & Science in Sports & Exercise (1987), this equation was derived from 343 healthy adults aged 30–69 who walked one mile as fast as possible (without running) and had their heart rate measured immediately at the finish (r = 0.88, standard error ≈ 5.0 mL/kg/min). Because it's a brisk walk rather than a maximal run, it's often preferred for older adults, beginners, or anyone for whom a maximal running test isn't appropriate.
Derived by Uth and colleagues (European Journal of Applied Physiology, 2004) from the Fick principle, using measured average ratios of maximal-to-resting stroke volume and oxygen extraction. It requires no exercise test at all — just your resting heart rate and your maximum heart rate (measured, or estimated from age using the Tanaka formula: 208 − 0.7 × age).
There's no single official "good" VO2 max — it depends heavily on your age, sex, and training status, and reference datasets differ from each other (see below). As a general orientation, higher VO2 max values are consistently associated with better measured aerobic fitness, and values decline with age in most people. For a full discussion of what different scores mean, see our Good VO2 Max by Age and Sex guide.
The most credible modern US reference values come from the FRIEND registry (Fitness Registry and the Importance of Exercise National Database), a peer-reviewed dataset of 7,783 directly lab-measured VO2 max tests (Kaminsky et al., Mayo Clinic Proceedings, 2015). The table below shows the 25th–50th–75th percentile range by decade of age.
| Age | Men (25th–50th–75th) | Women (25th–50th–75th) |
|---|---|---|
| 20–29 | 40.1 – 48.0 – 55.2 | 30.5 – 37.6 – 44.7 |
| 30–39 | 35.9 – 42.4 – 49.2 | 25.3 – 30.2 – 36.1 |
| 40–49 | 31.9 – 37.8 – 45.0 | 22.1 – 26.7 – 32.4 |
| 50–59 | 27.1 – 32.6 – 39.7 | 19.9 – 23.4 – 27.6 |
| 60–69 | 23.7 – 28.2 – 34.5 | 17.2 – 20.0 – 23.8 |
| 70–79 | 20.4 – 24.4 – 30.4 | 15.6 – 18.3 – 20.8 |
Relative VO2 max (mL/kg/min) — the number this calculator reports — divides oxygen use by body weight, which is why it's used to compare fitness between people of different sizes. Absolute VO2 (L/min) is the total volume of oxygen your body uses per minute, regardless of body weight: absolute VO2 (L/min) = relative VO2 (mL/kg/min) × weight (kg) ÷ 1000. Absolute VO2 matters more for total work capacity (for example, how much load you can move), while relative VO2 matters more for endurance activities like running where you carry your own body weight.
VO2 max and heart rate are related but answer different questions. VO2 max estimates your aerobic capacity — how much oxygen your body can use at maximum effort. Heart rate training zones (see our Target Heart Rate Calculator, which uses the Karvonen method) tell you what intensity you're working at right now, relative to your own max and resting heart rate. You can use heart rate zones during training regardless of whether you know your VO2 max, and a higher VO2 max doesn't automatically mean a different target zone — it means you can likely sustain a higher absolute pace within the same relative zone.
A laboratory cardiopulmonary exercise test remains the gold standard, measuring oxygen consumption directly via gas-exchange analysis. Field tests like the ones in this calculator estimate VO2 max indirectly from performance or heart rate, using regression equations built from a specific sample — so their accuracy is inherently lower and varies by method (Cooper: r≈0.90; Rockport: r≈0.88, SEE≈5.0 mL/kg/min; Heart Rate Ratio: validated in a small, male-only sample). Consumer wearables (smartwatches, fitness trackers) use their own proprietary algorithms, typically based on heart rate and pace during regular runs, and their accuracy varies by brand and hasn't been independently verified against lab testing to the same extent as the equations used here. Treat any field-test or wearable VO2 max estimate as a useful trend indicator rather than an exact figure.
What is VO2 max?
VO2 max is the maximum rate at which your body can take up and use oxygen during intense exercise, measured in millilitres of oxygen per kilogram of body weight per minute (mL/kg/min). It's the standard scientific measure of cardiorespiratory fitness.
How do you calculate VO2 max?
VO2 max is directly measured in a lab using a gas-exchange exercise test. Without lab access, it can be estimated from a field test — such as the distance you cover in the Cooper 12-minute run, your time on the Rockport 1-mile walk, or the ratio between your resting and maximum heart rate — using validated regression equations like the ones in this calculator.
What is a good VO2 max?
It depends heavily on your age and sex — there's no single universal "good" number. Peer-reviewed FRIEND registry data shows the median VO2 max for men aged 20-29 is about 48 mL/kg/min, falling to about 24 by ages 70-79; for women the median is about 38 falling to about 18 over the same age range. See our Good VO2 Max by Age and Sex guide for full context.
What does VO2 max measure?
VO2 max measures your cardiorespiratory (aerobic) fitness — how efficiently your heart, lungs and muscles work together to deliver and use oxygen during sustained, intense exercise. It does not measure strength, flexibility, or overall health, and cannot diagnose any medical condition.
What is the Cooper test?
The Cooper test is a 12-minute maximal-effort run developed by Kenneth Cooper in 1968. You cover as much distance as possible in exactly 12 minutes, then use the formula VO2max = (distance in metres − 504.9) ÷ 44.73 to estimate your VO2 max. The original equation was derived from running, not walking.
Can you estimate VO2 max without a lab or exercise test?
Yes, using the heart rate ratio method (VO2max = 15 × max heart rate ÷ resting heart rate), which requires no exercise at all. It's the least precise of the methods offered here, especially if your max heart rate is also estimated from age rather than measured directly.
Does VO2 max decline with age?
Yes. FRIEND registry data shows VO2 max declining by roughly 9-10% per decade on average in adulthood, in both men and women, though the rate can be slower in people who continue training.
What is the difference between relative and absolute VO2 max?
Relative VO2 max (mL/kg/min) divides oxygen use by body weight, allowing comparison between people of different sizes — it's what's usually reported. Absolute VO2 (L/min) is your total oxygen use regardless of body weight, calculated as relative VO2 × weight (kg) ÷ 1000.
Is a VO2 max calculator as accurate as a lab test?
No. Field-test calculators like this one estimate VO2 max from performance or heart rate data using regression equations, which carry a real margin of error (roughly 5 mL/kg/min or more depending on method). A laboratory cardiopulmonary exercise test, measuring gas exchange directly, remains the gold standard.