VO2 Max Calculator
Estimate VO2 max from a Cooper 12-minute run or a race result (Daniels and Gilbert). Outputs mL/kg/min and a fitness group for your age and sex (Mandsager 2018).
VO2 Max Calculator
How to use the VO2 Max Calculator
Pick your estimation method
Race result: your time for a race of 5 km to the marathon, run through the Daniels and Gilbert model. Shorter races are refused rather than estimated. Cooper test: the distance you cover in a 12-minute all-out run on a measured track. Both are estimates; only a laboratory test with gas analysis measures VO2 max.
For a race result: use a true effort
Use a recent race run as hard as you could, on an accurately measured, flat course. The model first works out the oxygen cost of your race pace, then divides by the share of VO2 max that can be held for that long — about 95% for a 22-minute 5K, about 82% for a 3-hour marathon — so longer races are not penalised for being run below maximum.
For the Cooper test: pace the 12 minutes
Warm up, then cover as much distance as you can in exactly 12 minutes. VO2 max = (metres − 504.9) ÷ 44.73. Starting too fast and fading, or holding back, both lower the result.
Read the group
The page places your estimate in one of the five groups Mandsager et al. (2018) used for 122,007 adults referred for treadmill testing, by age and sex: low (below the 25th percentile), below average, above average, high, and elite (97.7th percentile or above). It also shows where the group lines fall for your age.
VO2 max — what the estimate means and how far to trust it
VO2 max is the most oxygen your body can use during all-out exercise, expressed per kilogram of body weight per minute (mL/kg/min); one MET is 3.5 mL/kg/min. A treadmill or cycle test with gas analysis measures it. This page estimates it from a performance instead, which is cheaper and less precise.
How the two estimates work
Cooper's 12-minute run turns distance into VO2 max with a straight line: (metres − 504.9) ÷ 44.73, so 2,400 m gives 42.4 mL/kg/min. The race method follows Daniels and Gilbert: it estimates the oxygen cost of running at your race speed, then divides by the share of VO2 max that can be sustained for the race's duration. On the defaults — 5 km in 22:30 — the oxygen cost is 41.0, the sustainable share is 94.6%, and VO2 max is about 43.4 mL/kg/min. This page used to print the oxygen cost alone as VO2 max, which under-read a 5K by about 5% and a 3-hour marathon by about 18%. The coefficients are Daniels and Gilbert's published ones (Oxygen Power, 1979); we could not obtain the original and use them as they are standardly reproduced.
The two methods can disagree for the same run
They are different equations, so one run can give two different numbers. Cooper's is a regression: a straight line fitted from 12-minute distance to measured VO2 max. Daniels and Gilbert's runs speed through an oxygen-cost curve and then divides by a sustainable share. Take 2,400 m covered in 12:00. The Cooper method gives 42.4 mL/kg/min. Daniels and Gilbert's formula, applied to the same 2.4 km in 12:00, gives an oxygen cost of 36.0 at 200 m/min and a sustainable share of 99.2%, so 36.3. That is 6.1 mL/kg/min lower, and for a man aged 32 the first lands in "above average" and the second in "below average". This page does not give the second figure itself, because 2.4 km is outside the 5 km to marathon range it states for the race method; the arithmetic is shown to explain the gap, not to say which number is right. Neither has been checked against a laboratory test for you.
A race tells you your pace; the model asks how close to your ceiling you could hold it for that long.
What the groups mean
The groups come from Table 2 of Mandsager et al. (JAMA Network Open, 2018), which classified 122,007 adults referred for exercise treadmill testing at one US centre by fitness for their age and sex. Over a median follow-up of 8.4 years, all-cause mortality fell with each step up: low performers had an adjusted hazard ratio of 5.04 against elite performers, and the study observed no upper limit to the benefit. The cut-offs fall with age — for men, "above average" starts at 12.0 METs (42.0 mL/kg/min) at 20–29 and 8.5 METs (29.8 mL/kg/min) at 60–69 — so the same result means more at 65 than at 25. Two cautions: the group is patients referred for testing, not a random sample, and its fitness was estimated from treadmill time, not measured by gas analysis.
How far to trust a field estimate
In a 2026 study of collegiate team-sport athletes (Soares et al., International Journal of Exercise Science), the Cooper test read 6.0 mL/kg/min below the laboratory value on average, with 95% limits of agreement from −19.8 to +7.9 mL/kg/min. A result in the "good or better" range was usually right, but a lower result often missed athletes who were fitter than it said. Use the estimate to follow your own trend over time under the same conditions, not as a diagnosis.
Cooper's line, Daniels' sustainable fraction, and what each fitness group means at your age
VO2 max is measured in mL/kg/min; 1 MET = 3.5 mL/kg/min.
Cooper: VO2 max = (metres in 12 minutes − 504.9) ÷ 44.73; 2,400 m gives 42.4.
Daniels and Gilbert divide the oxygen cost of race pace by the share of VO2 max sustainable for the race's duration.
On the defaults, a 22:30 5K costs 41.0 mL/kg/min at 94.6% of VO2 max: an estimate of 43.4.
For a 3-hour marathon the sustainable share is about 82%, so the oxygen cost alone under-reads by about 18%.
Mandsager et al. 2018: low performers had 5.04 times the adjusted mortality of elite performers over a median 8.4 years.
In that study, the benefit of higher fitness had no observed upper limit.
For men, “above average” starts at 42.0 mL/kg/min at 20–29 and 29.8 at 60–69.
The Cooper test read 6.0 mL/kg/min low on average in collegiate athletes (Soares et al. 2026).
Only a laboratory test with gas analysis measures VO2 max; both methods here estimate it.
Frequently Asked Questions
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Less accurate than it looks. In collegiate team-sport athletes the Cooper test averaged 6.0 mL/kg/min below the laboratory value, with 95% limits of agreement from 19.8 below to 7.9 above (Soares et al. 2026). The race method depends on a true effort, an accurate course and good pacing. Use either to follow your own trend under the same conditions; a laboratory test with gas analysis is the only measurement.
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Not necessarily, and the two can give quite different numbers for the same runner (see "The two methods can disagree for the same run" above). The race method has two practical advantages: a race is usually paced and run harder than a solo time trial, and it can use any distance from 5K to the marathon. Its weakness is that it assumes you were running at your limit for the whole race; a hot day, hills, a poorly measured course or an easy effort all make the estimate low.
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Watches estimate VO2 max from your heart rate against your running speed, using their own undisclosed models, so they will rarely match a race-based or Cooper estimate exactly. Compare like with like: the same method, under similar conditions, over time.
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That varies with your starting fitness, age and training, and this page does not cite a figure for it. The useful test is repeat measurement: run the same test under similar conditions every couple of months and watch the trend.
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On average, yes, and the reference groups reflect it. In Mandsager et al.'s table, the line between below and above average for men falls from 12.0 METs (42.0 mL/kg/min) at 20–29 to 8.5 METs (29.8) at 60–69, and for women from 10.0 METs (35.0) to 7.0 METs (24.5). That is why this page places your result against your own age and sex.
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This page does not rank training methods; it estimates where you are now. Whatever plan you follow, retest with the same method under similar conditions to see whether it is working, and get medical advice before starting hard training if you have a heart condition or symptoms.
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VO2 max is the ceiling: the most oxygen you can use at all-out effort. Lactate threshold is the hardest effort you can sustain before lactate builds up faster than it is cleared, a fraction of that ceiling. Two runners with the same VO2 max can race differently because one can hold a larger share of it — which is exactly what the race method's sustainable-fraction term models.
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Sports-medicine clinics, university exercise-physiology laboratories and some hospitals offer cardiopulmonary exercise testing, a treadmill or cycle test with gas analysis. A doctor may also refer you for one for medical reasons. Ask what protocol is used, so a later retest is comparable.
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No. The calculation runs in your browser, and the age, sex, distance and time you enter are not sent to our server or saved. The page itself still makes ordinary requests as it loads, such as its scripts and site settings.
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Pair with: Race Time Predictor for race-distance time predictions; Running Pace Calculator for target-time pacing; Sweat Rate Calculator for hydration planning; Cycling FTP Calculator if you also cycle.
Method & sources
How it computes
Cooper: VO2 max = (metres in 12 min - 504.9) / 44.73. Race: Daniels & Gilbert, oxygen cost -4.60 + 0.182258v + 0.000104v^2 (v m/min) divided by the fraction sustainable for t minutes, 0.8 + 0.1894393e^(-0.012778t) + 0.2989558e^(-0.1932605t). Group by age and sex from Mandsager et al. 2018 Table 2 (METs x 3.5). RecaFitness, tested.
What this tool implements
- Bug fixed: the race method printed only the oxygen cost of race pace as VO2 max, omitting Daniels and Gilbert's sustainable-fraction term, so every race under-read: the default 22:30 5K by 5.4% (41.0 for 43.4), a 3-hour marathon by about 18%. The coefficients are the published 1979 ones; the original book could not be obtained, and the page says so.
- Categories replaced: an untraceable 'Cooper Institute / ACSM' table (very low to superior) gave way to Mandsager et al.'s Table 2 groups (low <25th, below average, above average, high, elite >=97.7th percentile) by age and sex, among 122,007 adults referred for treadmill testing at one centre; low vs elite adjusted mortality HR 5.04, median follow-up 8.4 years, no observed upper limit. Accuracy now from Soares et al. 2026: Cooper read 6.0 mL/kg/min low on average, limits -19.8 to +7.9.
- Removed as unsourced: '50-80% lower mortality', '5-7 years longer', '50-70% genetic', '10% a decade', test accuracies of +/-2-15%, lab-test prices, 4x4 'gold standard', trainability percentages, heat and humidity effects, elite VO2 ranges, ASEAN clinic names.
Sources
- Mandsager K, Harb S, Cremer P, Phelan D, Nissen SE, Jaber W. Association of cardiorespiratory fitness with long-term mortality among adults undergoing exercise treadmill testing. JAMA Netw Open. 2018;1(6):e183605 (Table 2). https://doi.org/10.1001/jamanetworkopen.2018.3605
- Soares EMKVK, Silva R, da Cruz CJG, et al. Cooper's 12 minute run systematically underestimates VO2max in collegiate team sport athletes: validity and classification accuracy. Int J Exerc Sci. 2026;19(2). https://doi.org/10.70252/IJES2026212
- Oficial-Casado F, et al. Performance prediction equation for the Valencia Marathon based on time and pacing in the half marathon (VDOT integrates VO2max, the fraction sustained and running economy). Front Physiol. 2025. https://doi.org/10.3389/fphys.2025.1718298
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