Fitness age calculator
Estimate your fitness age from VO2max
Enter your chronological age, sex and a known VO2max, or use your distance from a Cooper 12-minute test. Add your usual resting heart rate if you know it. This gives a browser estimate from a few inputs, not a medical or biological-age test.
Use a usual resting heart rate from your baseline, not the heart rate from one workout. The Complete app gathers a fuller history for its own number.
Need to work out your VO2max first? The separate calculator accepts a Cooper distance and shows the formula. VO2max calculator
For a separate estimate based on age and heart rate, use the heart rate zone calculator. Heart rate zone calculator
The two inputs in the estimate
The score turns each available value into a percentile against a norm table for your age bracket and sex. The scorer gives VO2max a 30% weight. A resting heart rate, when you add it, carries 20%. The calculator leaves a blank optional value out of the denominator rather than treating it as zero.
A lower resting heart rate earns a higher percentile. With both values present, the available inputs become 60% VO2max and 40% resting heart rate after normalization. With no resting heart rate, VO2max carries the whole score, so the result remains a VO2max-only estimate.
| Input | Weight | When it counts |
|---|---|---|
| VO2max | 30% | Required for this calculator |
| Usual resting heart rate | 20% | Optional; blank means it is left out |
VO2max from a Cooper test
You can type a known VO2max or switch to a Cooper 12-minute distance. This calculator uses Complete's app transform: VO2max = 0.022351 × distance in metres - 11.288, in ml/kg/min. It accepts distances from 600 metres, and the result is an estimate from a run, not a lab measurement.
The public VO2max chart uses a different Cooper formula, so its result can differ. This page uses the app transform so its fitness-age estimate follows the app source.
Complete also has a treadmill Ramp test. The app uses the speed held in that test for its VO2max estimate, while a Cooper test is the outdoor fallback. This page only uses the value you enter or the Cooper distance you type.
From score to fitness age
The score starts at 50 for the middle of a norm group. The age rule moves the estimate one year for every full five points above or below 50. Scores from 46 through 54 leave it unchanged; 55 moves it one year younger and 45 moves it one year older.
The rule keeps the estimate within 9 years of your chronological age in either direction, and it never goes below 18. Treat the result as a rough estimate from a few inputs, not as a diagnosis or a biological-age test.
How this differs from Complete Age
Complete Age is the app number. Its scorer uses the most recent saved VO2max and a 90-day median resting heart rate from one wearable source when enough history exists. The app can use other signals too, so this short calculator does not reproduce the app result.
The app gathers a fuller history rather than treating a single workout heart rate as your baseline. Use this page to get an estimate from the few values you have, then use the app if you want the longer view of your fitness journey.
Frequently asked questions
Is this a biological age test?
No. This is a fitness-age estimate from a few typed values, not a medical test or a direct measure of biological age. Complete Age uses a fuller history in the app, and neither number is a diagnosis.
What does fitness age mean here?
It is an age-style estimate made from your VO2max percentile and, if you add it, your usual resting-heart-rate percentile. It is not a medical or biological-age test.
Can I use a Cooper 12-minute test?
Yes. Switch the input to Cooper distance and enter the metres you ran in 12 minutes. The formula turns that distance into an estimated VO2max.
Should I enter the heart rate from my workout?
No. If you add resting heart rate, use your usual baseline value. A single workout heart rate is not a resting baseline, and the Complete app uses a fuller history for its own value.
Does a blank resting heart rate make the result zero?
No. The optional resting-heart-rate dimension is left out, and the VO2max dimension carries the score by itself.
Is this the same number as Complete Age?
No. Complete Age uses the live app scorer and the data available in your account. This page uses only the values you type, so the two estimates can differ.
Does the calculator save my values?
No. The calculation runs in your browser. Nothing you type here is saved or sent.
Related
Sources
- Cooper KH. A means of assessing maximal oxygen intake. JAMA, 1968;203(3):201-204 checked 26 Oct 2026
- Complete Age method: inputs, weights and score-to-age rule, reviewed 2026-10-25 checked 26 Oct 2026
Keep the longer view
Over time, Complete gets to know your body with saved VO2max and history-based recovery inputs. Use the estimate above as a starting point for your own context.