FitAge

Fitness Age Calculator

Are you fitter than your age suggests? Find out.

Chronological age

VO₂ max

Fitness age

28.6

Rough model: chronological age adjusted by how far VO₂max is above/below the average for your age.

What you entered

Chronological age: 30VO₂ max: 45

1
Average VO₂ max for your age
48 − 0.5 × max(0, 30−20)= 43.0 ml/kg/min
2
Compare to your VO₂ max
45 − 43.0= 2.0 ml/kg/min
3
Adjust chronological age
30 − (2.0 × 0.7)= 28.6 years

Result

Fitness age: 28.6

At chronological age 30 with a VO₂ max of 45, your fitness age is 28.6.

Fitness age from VO2 max

Fitness age compares your VO2 max against the average for each age. A VO2 max above average for your years pulls your fitness age below your real one.

Actual age	VO2 max	Fitness age	Difference
25	55	18.4	6.6 years younger
30	45	28.6	1.4 years younger
40	45	35.1	4.9 years younger
40	35	42.1	2.1 years older
50	40	45.1	4.9 years younger

The same VO2 max of 45 reads as slightly better than average at 30 and clearly above average at 40, because the population average declines with age. General wellness information only, not medical advice. Discuss any health decision with a qualified clinician.

A cardiovascular age, not a birthday

Fitness age compares your VO₂ max against population norms for different ages — a 50-year-old with the VO₂ max typical of a 35-year-old gets a fitness age of 35, a motivating reframe of raw fitness numbers.

Why this framing motivates people

Research popularizing this metric (notably from Norway's HUNT study) found that fitness age tends to resonate more with people than an abstract VO₂ number, since 'you're 10 years younger than your age' is instantly meaningful.

Frequently asked questions

What determines fitness age?

Primarily your VO₂ max relative to age and sex norms. A 45-year-old with the VO₂ max typical of a 30-year-old has a fitness age of 30. The HUNT study (Norwegian University of Science and Technology) showed that fitness age predicts mortality better than chronological age.

Can you reverse your fitness age?

Yes. Consistent aerobic exercise (especially HIIT) can improve VO₂ max by 15–20% in 3–6 months, potentially dropping fitness age by 10–20 years. Studies show that previously sedentary adults who begin regular exercise can achieve fitness ages significantly younger than their chronological age within a year.

How is fitness age different from biological age?

Fitness age focuses specifically on cardiovascular fitness (VO₂ max). Biological age uses broader markers: blood biomarkers, telomere length, DNA methylation, and multiple organ function tests. Fitness age is easier to measure and actionable — you know exactly what to do to improve it (exercise more).