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Calculator Answers

VO2 Max Calculator

Source: Cooper KH. A means of assessing maximal oxygen intake. Correlation between field and treadmill testing. JAMA. 1968;203(3):201-204. Source of the 12-minute run, the default protocol here. The Rockport walk is a separate equation from Kline GM et al, Med Sci Sports Exerc. 1987;19(3):253-259, cited in full on the page · Source verified August 15, 2026

Blake Boege
Written by Blake Boege · Founder, Calculator Answers

VO2 max, or maximal oxygen uptake, is the maximum rate of oxygen consumption measured during incremental exercise, reflecting an individual's cardiorespiratory fitness and aerobic endurance. A VO2 max calculator estimates this metric from a published field test rather than measuring it. Two protocols are implemented: the Cooper twelve-minute run (Cooper 1968) and the Rockport one-mile walk (Kline 1987), each with its own equation and its own source. By entering the test result alongside the inputs that protocol requires, the calculator runs the published regression and reports an estimate in mL/kg/min. It assigns no fitness category, because a defensible one needs a cited normative table matched to age, sex and population. Athletes and coaches use this utility to track cardiovascular improvement and design endurance training intensities.

Pick a field test, enter your result, and the calculator runs the protocol's published equation to estimate VO2 max in mL/kg/min. It shows the equation it used and the group of people that equation was built from, because a field-test estimate is only as transferable as the study behind it.

See also: Pace Calculator, Target Heart Rate Calculator, and Max Heart Rate Calculator.

Quick Answer

Estimate VO2 max in mL/kg/min from a field test. Pick the Cooper 12-minute run or the Rockport 1-mile walk, enter your result, and the calculator runs that protocol published equation. No fitness rating is assigned.

Field test

m

Six laps of a standard 400 m track is 2,400 m.

The Cooper equation uses distance alone. Age, sex and body weight are not part of it, so this mode does not ask for them.

What this number is

A field-test estimate produced by a published regression, not a measurement. Laboratory testing measures VO2 max directly with a metabolic cart; a stopwatch and a track cannot do the same thing. Each equation was fitted to a particular group of people, and the further you are from that group the looser the estimate becomes.

This page reports a number. It does not assess your health. Hard or maximal-effort testing is not appropriate for everyone, so speak to a clinician first if that applies to you.

VO2 max estimate

Estimated VO2 max

42.4 mL/kg/min

Cooper 12-minute run field-test estimate

ProtocolCooper 12-minute run
Equation(2,400 - 504.9) / 44.73
Estimated VO2 max42.4 mL/kg/min
How the test is runCover as much ground as you can in 12 minutes on a flat course or track.
Equation populationCooper's original regression was developed in United States Air Force personnel.

Most useful as a baseline to compare against your own later results on the same protocol. Comparing an estimate from one protocol against an estimate from another, or against a lab value, mixes methods that do not agree closely.

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Examples

Cooper: 2,400 m in 12 minutes

≈ 42.4 mL/kg/min

Cooper: 3,000 m in 12 minutes

≈ 55.8 mL/kg/min

Rockport: 160 lb, age 30, male term, 15:00 walk, HR 140

≈ 44.3 mL/kg/min

Rockport: 200 lb, age 45, female term, 18:00 walk, HR 150

≈ 17.8 mL/kg/min

How it works

Formula · Cooper 12-minute run: VO2 max = (distance in metres − 504.9) ÷ 44.73. Rockport 1-mile walk: VO2 max = 132.853 − 0.0769 × weight lb − 0.3877 × age + 6.315 × sex − 3.2649 × time min − 0.1565 × heart rate

Neither protocol measures oxygen. Each one was built by testing a group of people in a laboratory, recording how they performed on a field test, and fitting a regression between the two. The equation you run here is that fitted line.

Cooper 12-minute run

VO2 max = (distance in metres − 504.9) ÷ 44.73

Distance is the only input. Age, sex and weight do not appear.

Rockport 1-mile walk

VO2 max = 132.853 − 0.0769·weightlb − 0.3877·age + 6.315·sex − 3.2649·timemin − 0.1565·HR

The parts

  • VO2 max = estimate in mL/kg/min
  • weight = body weight in pounds
  • age = years
  • sex = the regression's binary term, 1 or 0
  • time = 1-mile walk time in minutes
  • HR = heart rate in bpm immediately at the finish

The two equations share no coefficients and are not interchangeable. Running a walk time through the Cooper equation, or a distance through the Rockport equation, produces a number with no meaning.

Both equations by hand

Each protocol is a single line of arithmetic once the test is done. Writing it out shows which input the estimate actually turns on.

Cooper, 2,400 m in 12 minutes

  1. Subtract the intercept. 2,400 − 504.9 = 1,895.1
  2. Divide by the slope. 1,895.1 ÷ 44.73 = 42.4 mL/kg/min
  3. Cover 3,000 m instead and the same two steps give 55.8. Six hundred metres of extra distance is worth about thirteen points, so the estimate is far more sensitive to effort than to anything else you could get wrong.

Rockport, 160 lb, 30 years, 15:00, 140 bpm

  1. Start at the intercept, then subtract each term: 132.853 − 0.0769(160) − 0.3877(30) − 3.2649(15) − 0.1565(140)
  2. Add the sex term, which contributes 6.315 when the equation is run as male and nothing when it is run as female.
  3. The two runs give 44.3 and 38.0 mL/kg/min. The gap between them is exactly the 6.315 coefficient, because that is the only term that changed.

That last point is worth sitting with. The sex term is a fitted coefficient from the 1987 study, not a statement about any individual. It shifts the estimate by a fixed amount because that is how the regression was built.

What the number is, and what it is not

VO2 max is a rate: the millilitres of oxygen your body can use per kilogram of body mass per minute at maximum effort. A laboratory measures it directly by analysing expired gas during a graded test to exhaustion. Neither protocol here does that. Both estimate that laboratory value from how far or how fast you moved, using an equation fitted to a group of people.

So the honest reading of the output is narrow: it is where your performance on this protocol falls, expressed on the scale the original study used. It is not a measurement of you, it is not a grade, and it is not a statement about your health. This page reports the figure and the equation that produced it, and stops there deliberately.

Edge cases, and where the equations stop making sense

  • Very short Cooper distances. Below 504.9 m the regression crosses zero and keeps going. A negative rate of oxygen consumption is not an unusual result, it is a sign the equation has been taken outside the range it was fitted on, and the calculator declines to print one.
  • Extreme Rockport inputs. Every term after the intercept subtracts, so a heavy, older, slow walker with a high finishing heart rate can drive the sum below zero. The same refusal applies.
  • A late pulse reading. The Rockport equation wants the heart rate taken immediately at the finish. A pulse counted a minute later has already fallen, and a lower heart rate raises the estimate. A ten beat error moves the result by about 1.6 points.
  • Mixing protocols. A walk time run through the Cooper equation is meaningless. The two were fitted separately, on different people doing different things, and their outputs are not directly comparable to each other either.
  • Submaximal effort. Both protocols assume the intended effort was actually sustained. Pacing yourself produces a lower estimate, which is a fact about the test rather than about your capacity.

Your figures stay in the page

Your age, weight, walk time and heart rate are processed by this page in your browser. They are not sent to a server, not stored after you close the tab, and not visible to anyone else. There is no account and nothing to sign up for. Health inputs deserve that treatment by default, not on request.

Worked example

Rockport walk: 160 lb, age 30, male term, 15:00 walk time, heart rate 140 at the finish.

  • start at 132.853
  • − 0.0769 × 160 = − 12.304
  • − 0.3877 × 30 = − 11.631
  • + 6.315 × 1 = + 6.315
  • − 3.2649 × 15 = − 48.974
  • − 0.1565 × 140 = − 21.910
  • total ≈ 44.3 mL/kg/min

Doing it by hand is worth once: it shows how heavily walk time and heart rate drive the result. Ten seconds faster over the mile moves the estimate by about half a point.

Assumptions and limitations

  • Each equation was fitted to a specific group. Cooper's came from United States Air Force personnel; Kline's came from 343 healthy adults aged 30 to 69. The further you sit from the group an equation was built on, the looser its estimate.
  • Both protocols assume the intended effort is actually sustained, on a flat measured course, with an accurate time.
  • The Rockport equation needs a heart rate taken immediately at the finish. A pulse counted a minute later has already dropped and will inflate the estimate.
  • This is an estimate of a laboratory measurement, not the measurement. No field test replaces direct gas analysis.
  • No normative category is shown, because publishing one responsibly requires a cited table matched to your age, sex and population rather than a rule of thumb.
  • Nothing here assesses health or fitness for exercise.

Sources

Related fitness calculators

Note. An estimate from a published field-test equation, for general information. It is not a medical test, it does not assess cardiovascular health, and it does not indicate whether any particular exercise is appropriate for you.

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Frequently asked questions

VO2 max is the highest rate at which your body can take in and use oxygen during hard exercise, reported in millilitres of oxygen per kilogram of body weight per minute (mL/kg/min). It is one of the standard measures of aerobic capacity.

They suit different people. The Cooper 12-minute run asks for a hard running effort and needs only a measured distance. The Rockport 1-mile walk is a walking protocol and suits people who do not want to or should not run, but it needs your age, body weight, walk time and your heart rate at the finish. Use whichever protocol you can actually perform properly, then stay with it, because estimates from different protocols are not directly comparable.

No. A laboratory test measures the oxygen you actually consume using a metabolic cart while the workload increases to exhaustion. This page runs a regression equation over a stopwatch result. It produces an estimate of that measurement, and the two are not interchangeable.

Because a defensible answer needs a normative table matched to your age, sex and the population it was built from, cited to whoever published it. The version that used to sit here generated its cut-offs from a formula rather than from any published table, which made the labels look authoritative without being traceable to anything. It has been removed rather than replaced with another approximation.

Its equation could not be traced to a source. The code ran one regression while its own comment named a different study's coefficients, so neither the number nor its provenance could be verified. Rather than keep an unsourced equation on a health page, the mode was removed. The two remaining protocols each cite the original published study.

This page does not answer that, and the reason is not evasiveness. Answering it responsibly needs a normative table matched to your age, sex and population, published by a named source, and applied to a laboratory measurement rather than a field-test estimate. Without all four of those, any category would be a rule of thumb dressed up as a finding. The page reports where your performance falls on the scale the original study used, and leaves interpretation to a source that can actually support it.

It is a rate: millilitres of oxygen used per kilogram of body mass per minute at maximum effort. Because it is divided by body mass, two people with the same absolute oxygen uptake will get different figures if they weigh different amounts. That is a property of the units, not a judgement about either person.

Less accurate than a laboratory test, and the gap is not a fixed offset you can correct for. Each equation carries the error of the regression it came from plus the error in your own execution of the protocol. Effort, pacing, surface, wind and heat all move the result. Treat a single figure as approximate and pay more attention to whether it changes over months under identical test conditions.

Because the 1987 Rockport study fitted a coefficient for it, and this page runs the published equation rather than a modified one. The term adds 6.315 when the equation is run as male and nothing when run as female, which is the entire difference between those two outputs. It is a fitted constant from that study population, not a statement about any individual.

Half of it, and the half matters. Cooper's 1968 paper in JAMA is readable only as its abstract, which confirms the study itself: "One hundred and fifteen US Air Force male officers and airmen were evaluated on a 12-minute field performance test and on a treadmill maximal-oxygen-consumption test", with a correlation of 0.897. That much is verified here directly. THE EQUATION IS NOT IN THE ABSTRACT. The body is paywalled, PubMed carries no abstract of its own, and no archive reached here holds the issue. So the (metres − 504.9) ÷ 44.73 form this page computes is taken from later peer-reviewed papers that print it and attribute it to Cooper, not from Cooper's own page. A second form, −11.288 + 22.351 × distance in km, also circulates, and it is worth knowing that it is not a rival. 22.351 per kilometre is 35.9704 per mile, so the two expressions agree to within 0.02 mL/kg/min across the useful range for the simple reason that they are THE SAME LINE written in different units. Until 22 August 2026 this page said the fourth significant figure of the slope was unsettled in the literature. That was wrong, and no source was needed to settle it: the arithmetic does.

Not directly. They are separate equations fitted on different people performing different tests, so the same person can get different numbers from each. Pick the protocol you can perform properly and stay with it, then compare your own results to each other over time.

The calculator declines to print a figure. Below 504.9 metres the Cooper regression crosses zero and continues into negative numbers, and the Rockport equation does the same for a heavy, older, slow walker with a high finishing heart rate. A negative rate of oxygen consumption is not an unusual estimate, it is a sign the equation has been used outside the range it was fitted on.

For the Rockport walk, precisely and immediately. The equation expects the rate at the finish, and a pulse counted even a minute later has already dropped. Ten beats of error moves the estimate by about 1.6 points, in the direction of flattering you, because a lower finishing heart rate reads as better fitness to the regression.

No. Nothing on this page assesses health or readiness for exercise, and neither protocol was designed for that. Both ask for a hard sustained effort, which is itself a decision worth taking with a clinician if you have any reason to.

No. Everything you enter is processed by the page in your browser. Nothing is sent to a server, nothing is stored after you close the tab, and there is no account.

Yes, substantially. Both protocols assume you sustain the intended effort for the whole test: as much ground as you can cover in the Cooper run, and as fast as you can walk without running in the Rockport test. A submaximal effort produces a lower estimate. Surface, wind, heat and pacing all move the number too.