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VO2 max calculator: three field tests
Short answer
You can estimate VO2 max without a lab. Cooper's 12-minute run uses (metres − 504.9) ÷ 44.73, so covering 2,400 m gives about 42.4 mL/kg/min. The Rockport one-mile walk adds age, sex, weight and finishing heart rate, and Uth's heart rate ratio, 15.3 × max HR ÷ resting HR, needs no exercise test at all.
Last reviewed 28 October 20264 published sourcesNot medical advice
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The three methods
Cooper 12-minute run: VO2 max = (distance in metres − 504.9) ÷ 44.73 (Cooper, 1968).
Rockport one-mile walk: Kline et al.'s equation gives VO2 max in litres per minute as 6.9652 + 0.0091 × weight (lb) − 0.0257 × age + 0.5955 × sex (1 for men, 0 for women) − 0.2240 × time (minutes) − 0.0115 × heart rate at the finish; dividing by body weight in kg and multiplying by 1,000 gives mL/kg/min (Kline et al., 1987). A 45-year-old woman weighing 68 kg who walks the mile in 15 minutes and finishes at 130 bpm gets about 34.1 mL/kg/min.
Heart rate ratio: VO2 max ≈ 15.3 × maximum heart rate ÷ resting heart rate (Uth et al., 2004). With a maximum of 185 and a resting rate of 60, that is about 47.2 mL/kg/min.
| Distance in 12 minutes | Miles | VO2 max (mL/kg/min) |
|---|---|---|
| 1,600 m | 0.99 | 24.5 |
| 1,800 m | 1.12 | 29.0 |
| 2,000 m | 1.24 | 33.4 |
| 2,200 m | 1.37 | 37.9 |
| 2,400 m | 1.49 | 42.4 |
| 2,600 m | 1.62 | 46.8 |
| 2,800 m | 1.74 | 51.3 |
| 3,000 m | 1.86 | 55.8 |
| 3,200 m | 1.99 | 60.3 |
| 3,400 m | 2.11 | 64.7 |
Comparing with your Apple Watch
Apple Watch estimates VO2 max, which it calls Cardio Fitness, from your heart rate on outdoor walks, runs and hikes (Apple Support: cardio fitness). Field tests and watch estimates are both predictions, so expect them to differ by a few points and follow the trend rather than one value.
To see where any of these numbers sits for your age and sex, open VO2 max by age. The heart rate ratio needs a maximum; the max heart rate calculator can predict one.
Your watch estimates this on every outdoor walk
Reps reads the Cardio Fitness (VO2 max) estimate your Apple Watch records and turns it into a fitness age with what is moving it.
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Common questions
How do I do the Cooper 12-minute run test?
Warm up, then run as far as you can in exactly 12 minutes on a flat, measured course such as a 400 m track, and note the distance. Cooper's 1968 equation converts the distance in metres to VO2 max: (distance − 504.9) ÷ 44.73. It is a maximal effort, so only do it if you are used to hard running.
How does the Rockport walk test work?
Walk one mile (1.609 km) as fast as you can on a flat course, then record your time and your heart rate at the finish. Kline et al. (1987) developed and cross-checked the equation in 343 adults aged 30 to 69, against treadmill-measured VO2 max. It suits people who would rather not run.
How accurate is the heart rate ratio method?
Uth et al. (2004) derived the factor of 15.3 in well-trained men aged 21 to 51. With a measured maximum heart rate, the estimate was within about 2.7 mL/kg/min on average; with an age-predicted maximum, about 4.7. The authors noted it still needs validating in other groups, including women and less-trained people.
Sources
Figures on this page were checked against these publications on 28 October 2026.
- Cooper KH. A means of assessing maximal oxygen intake: correlation between field and treadmill testing. JAMA. 1968;203(3):201–204. doi.org/10.1001/jama.1968.03140030033008
- Kline GM, Porcari JP, Hintermeister R, Freedson PS, Ward A, McCarron RF, Ross J, Rippe JM. Estimation of VO2max from a one-mile track walk, gender, age, and body weight. Medicine & Science in Sports & Exercise. 1987;19(3):253–259. doi.org/10.1249/00005768-198706000-00012
- Uth N, Sørensen H, Overgaard K, Pedersen PK. Estimation of VO2max from the ratio between HRmax and HRrest: the Heart Rate Ratio Method. European Journal of Applied Physiology. 2004;91(1):111–115. doi.org/10.1007/s00421-003-0988-y
- Apple. Track your cardio fitness levels. Apple Support. support.apple.com/en-us/108790
More heart tools
- Resting heart rate by ageSee where your resting heart rate falls among people your age and sex, using national NHANES percentiles.
- VO2 max by ageCompare your Apple Watch Cardio Fitness with measured treadmill VO2 max percentiles by age and sex.
- Heart rate recoveryCalculate your one-minute heart rate recovery and see how Apple Watch Cardio Recovery is measured.
- Max heart rate calculatorYour age-predicted maximum heart rate from four published formulas.