Estimate relative aerobic capacity from a Cooper 12-minute run, a Rockport one-mile walk, or measured maximum and resting heart rates. Pick the method that matches data you actually collected.
Three published methodsRun, walk, or heart-rate inputs with method-specific assumptions.
Useful conversionsSee mL/kg/min, METs, and optional litres of oxygen per minute.
Private by designNothing you enter is uploaded, stored, or used to track you.
Estimate your VO₂ max
For adults. This is an educational field estimate—not a diagnosis, fitness clearance, or laboratory measurement.
Prepared by: Starlight Tools editorial team. Last reviewed: July 29, 2026.
Method basis: Cooper distance equation, Kline/Rockport one-mile walk equation, and the Uth heart-rate-ratio equation. Sources are linked below.
Privacy: Calculations run only in this browser tab. Inputs are not saved or sent anywhere by this tool.
Estimated result
Choose a method and enter your test data.
—mL O₂/kg/min
MET equivalent—
Estimated absolute VO₂Add body weight
Equation calculation—
Your method limits and interpretation notes will appear here. Compare repeated results only when test conditions and method are similar.
What the result means
Relative VO₂ max describes oxygen use relative to body mass and is reported as millilitres of oxygen per kilogram per minute (mL/kg/min). That makes comparisons less dependent on body size.
Absolute VO₂ is estimated in litres per minute when body weight is available. It is a conversion of the predicted relative result, not a separate measurement.
METs are calculated using the conventional conversion of 1 MET = 3.5 mL/kg/min. The displayed MET value is an aerobic-capacity equivalent, not the intensity of your test.
How to get a more repeatable estimate
Use the same method, route, equipment, and time-measurement approach.
Avoid testing when ill, unusually fatigued, dehydrated, or in extreme weather.
For Rockport, walk rather than jog and capture the finish heart rate immediately.
Track trends over several tests rather than treating one result as exact.
Equations and assumptions
Cooper 12-minute run
VO₂ max = (distance in metres − 504.9) ÷ 44.73
The distance equation assumes a continuous, maximal-effort 12-minute run. Pacing, surface, wind, temperature, GPS error, and motivation can affect the result.
The equation codes male as 1 and female as 0. It was developed from healthy adults aged 30–69 who completed timed one-mile track walks, so estimates outside that population need extra caution.
Heart-rate ratio
VO₂ max = 15.3 × (measured HRmax ÷ resting HR)
The original 15.3 factor was studied in well-trained men aged 21–51. The authors reported greater prediction error when measured maximum heart rate was replaced with an age-predicted value. Generalisation to other populations is limited.
Safety and medical limits
This calculator cannot assess whether maximal or brisk exercise is safe for you. The Cooper test is maximal effort; Rockport is submaximal but still strenuous for some people. If you have a chronic health condition, disability, known heart or lung disease, are pregnant, take heart-rate-altering medication, or are unsure about exertion, ask a qualified health professional what testing is appropriate.
Stop exercise and seek appropriate medical help for warning symptoms such as chest pressure or pain, dizziness, faintness, unusual or extreme breathlessness, or a fast or irregular heartbeat. Do not use this estimate to diagnose disease, determine treatment, or replace a supervised cardiopulmonary exercise test.
Worked examples
Cooper run example
A runner covers 2,400 m in 12 minutes:
(2,400 − 504.9) ÷ 44.73 = 42.4 mL/kg/min
That equals about 12.1 METs. At 75 kg, the converted absolute estimate is about 3.18 L/min.
Rockport walk example
A 40-year-old man weighing 180 lb walks one mile in 14:00 with a finish pulse of 150 bpm:
Small timing or pulse differences can noticeably change the result, so consistent measurement matters.
Sources and methodology
Cooper KH. (1968). A means of assessing maximal oxygen intake: correlation between field and treadmill testing. JAMA, 203(3), 201–204. DOI: 10.1001/jama.1968.03140030033008.
Kline GM, Porcari JP, Hintermeister R, et al. (1987). Estimation of VO2max from a one-mile track walk, gender, age, and body weight. Medicine & Science in Sports & Exercise, 19(3), 253–259. PubMed record.
Uth N, Sørensen H, Overgaard K, Pedersen PK. (2004). Estimation of VO2max from the ratio between HRmax and HRrest—the Heart Rate Ratio Method. European Journal of Applied Physiology, 91, 111–115. DOI: 10.1007/s00421-003-0988-y.
Penry JT, Wilcox AR, Yun J. (2011). Validity and reliability analysis of Cooper's 12-minute run and the multistage shuttle run in healthy adults. Journal of Strength and Conditioning Research, 25(3), 597–605. DOI: 10.1519/JSC.0b013e3181cc2423.
Method note: equations are implemented as published and unit conversions use 1 mile = 1,609.344 m, 1 yard = 0.9144 m, and 1 kg = 2.2046226218 lb. Inputs are range-checked for likely entry errors; a valid result can still differ from measured VO₂ max.
VO₂ Max Estimator FAQ
What is VO₂ max?
VO₂ max is the maximum rate at which the body can take in and use oxygen during intense exercise. Relative VO₂ max is commonly expressed in millilitres of oxygen per kilogram of body mass per minute.
Is an estimated VO₂ max the same as a lab measurement?
No. Field equations predict VO₂ max from performance or heart-rate data. A supervised cardiopulmonary exercise test with respiratory gas analysis directly measures oxygen uptake and is the reference method.
Which VO₂ max estimation method should I use?
Use Cooper after a maximal 12-minute run, Rockport after a brisk one-mile walk with an immediate finish heart rate, or heart-rate ratio when you have measured resting and maximum heart rates. Use the same method when tracking change.
Can I use a predicted maximum heart rate?
This calculator asks for a measured maximum heart rate because the original heart-rate-ratio study reported more error when maximum heart rate was age-predicted. Do not perform a maximal test unless it is appropriate and safe for you.
Why can different methods give different VO₂ max results?
Each equation was developed in a different sample and responds to different inputs. Pacing, terrain, weather, fatigue, pulse measurement, medication, and how closely you match the original study population can all change the estimate.
Does this calculator store my fitness data?
No. The calculation runs in your browser and this tool does not upload, save, or track the values you enter.
