VO₂max.io

Free biological age calculator

Biological age calculator

Check your biological age from six things you can measure at home. See which factors make you older or younger than your birthday, and what to do about it.

Don't know it? Do the beep or Cooper test first; the result is carried over.
Brisk walking and harder. Count vigorous minutes twice.
Not a medical assessment. This is a simple estimate for interest and motivation. Check with a doctor before hard training if you have heart problems.

How the estimate works

Large studies give a number for how much each factor raises or lowers the risk of dying early, called a hazard ratio. Statistician David Spiegelhalter showed that such a number can be turned into years of “effective age”: years ≈ 10 × ln(hazard ratio). We add up the years from each factor and add them to your age.

FactorStudy figureOur starting point
Fitness (VO₂ max)0.87 per 1 MET (3.5 ml/kg/min) higher (Kodama 2009)Median for your age and sex (FRIEND 2015); counted up to ±4 MET
Resting heart rate1.09 per 10 bpm higher (Zhang 2016)60 bpm; counted from 40 to 100
Waist-to-height ratio1.24 per 0.1 higher; lowest risk near 0.5 (Jayedi 2020)0.5; nothing subtracted below it
SleepShort 1.12, long 1.30 (Cappuccio 2010)Under 7 h is short, 9 h or more is long
SmokingCurrent 2.8 (men) / 3.0 (women); former 1.20–1.74 by quit age, about the same as never if quit before 35 (Jha 2013)Never smoked
Exercise0.80, 0.69, 0.63, 0.61 for under 150, 150–299, 300–449, 450+ min a week, compared with none (Arem 2015)150 minutes a week

The starting points and limits are our choices to keep the numbers reasonable. Fitness age is the age at which the median VO₂ max equals yours, an idea from the Norwegian HUNT fitness studies (Nes 2014), here worked out with the US FRIEND table.

Limits, in plain words

  • The factors overlap. Fit people tend to have a lower resting heart rate and exercise more, so adding them can count the same thing twice.
  • The studies show links in large groups, not cause and effect for one person.
  • Blood pressure, blood sugar, cholesterol, genes and illness are not included.
  • It is not the same as a lab “biological age” test from blood or DNA.

What lowers your number

Fitness is the factor that responds fastest to training. Try the Norwegian 4×4, 30/30 intervals, HIIT twice a week or the Tabata timer, and retest with the beep or Cooper test calculator after 6–8 weeks. Compare your VO₂ max with others on VO₂ max by age.

FAQ

How accurate is a biological age calculator?

This one is a rough estimate. It adds up how much each factor is linked to risk in large studies. It cannot see your genes, blood values or medical history, so treat it as a guide to what you can change, not as a measurement.

How can I check my biological age for free?

Fill in the form above. For the best result, measure your VO₂ max with a beep test or Cooper test and your resting heart rate in the morning.

Is biological age the same as metabolic age?

Not quite. Scales that show a metabolic age usually compare your estimated resting energy use with averages for each age. This page uses fitness, heart rate, waist, sleep, smoking and exercise instead.

Which factor matters most?

For most people smoking, fitness and exercise make the biggest difference. Fitness can be raised at any age with regular training.

Sources

  1. Spiegelhalter D. How old are you, really? Communicating chronic risk through ‘effective age’ of your body and organs. BMC Med Inform Decis Mak 2016;16:96. doi:10.1186/s12911-016-0342-z
  2. Kodama S, Saito K, Tanaka S, et al. Cardiorespiratory fitness as a quantitative predictor of all-cause mortality and cardiovascular events in healthy men and women: a meta-analysis. JAMA 2009;301(19):2024–2035. doi:10.1001/jama.2009.681
  3. Kaminsky LA, Arena R, Myers J. Reference standards for cardiorespiratory fitness measured with cardiopulmonary exercise testing: data from the Fitness Registry and the Importance of Exercise National Database. Mayo Clin Proc 2015;90(11):1515–1523, Table 3. doi:10.1016/j.mayocp.2015.07.026 (free: PMC4919021)
  4. Nes BM, Vatten LJ, Nauman J, Janszky I, Wisløff U. A simple nonexercise model of cardiorespiratory fitness predicts long-term mortality. Med Sci Sports Exerc 2014;46(6):1159–1165. doi:10.1249/MSS.0000000000000219
  5. Zhang D, Shen X, Qi X. Resting heart rate and all-cause and cardiovascular mortality in the general population: a meta-analysis. CMAJ 2016;188(3):E53–E63. doi:10.1503/cmaj.150535
  6. Jayedi A, Soltani S, Zargar MS, Khan TA, Shab-Bidar S. Central fatness and risk of all cause mortality: systematic review and dose-response meta-analysis of 72 prospective cohort studies. BMJ 2020;370:m3324. doi:10.1136/bmj.m3324
  7. Cappuccio FP, D’Elia L, Strazzullo P, Miller MA. Sleep duration and all-cause mortality: a systematic review and meta-analysis of prospective studies. Sleep 2010;33(5):585–592. doi:10.1093/sleep/33.5.585
  8. Jha P, Ramasundarahettige C, Landsman V, et al. 21st-century hazards of smoking and benefits of cessation in the United States. N Engl J Med 2013;368(4):341–350. doi:10.1056/NEJMsa1211128
  9. Arem H, Moore SC, Patel A, et al. Leisure time physical activity and mortality: a detailed pooled analysis of the dose-response relationship. JAMA Intern Med 2015;175(6):959–967. doi:10.1001/jamainternmed.2015.0533

Last updated: October 24, 2026. Written with AI assistance from the sources above. Not medically reviewed.