What is metabolic age?

Metabolic age compares your basal metabolic rate (BMR) to the average BMR for different ages. If your BMR matches that of a younger average person, your metabolic age is lower than your real age. It is an estimate popularised by body-composition scales, not a clinical measurement.

How is metabolic age calculated here?

The tool computes your BMR with the Mifflin-St Jeor equation, then scans reference ages 15–80 for a same-sex person of average height and weight and reports the age whose BMR is closest to yours.

What does it mean if my metabolic age is lower than my real age?

It means your resting metabolism matches that of an average person younger than you, which is generally a good sign and is often linked to more muscle mass and better fitness.

Is the Mifflin-St Jeor equation accurate?

It is the most accurate widely-used predictive BMR formula for the general population, but it is still an estimate. Actual BMR varies with body composition, genetics and health, which a height-and-weight formula cannot capture.

How can I lower my metabolic age?

Because BMR rises with lean mass, strength training and maintaining muscle tend to raise your BMR and lower the estimated metabolic age. This tool only estimates the number; it does not give medical advice.

Is this a medical test?

No. It is an informational estimate based on population averages, not a clinical or diagnostic measurement.

Is anything uploaded?

No. All calculations happen locally in your browser.

Metabolic Age Calculator

Metabolic age calculator

Metabolic age estimates how your basal metabolic rate (BMR) — the energy your body burns at rest — compares to population averages, then reports the age whose average BMR matches yours. A lower number is generally a positive sign.

How it works

First the tool computes your BMR using the Mifflin-St Jeor equation:

BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age + s

where s is +5 for men and −161 for women. It then holds a same-sex reference body fixed (about 176 cm / 78 kg for men, 163 cm / 65 kg for women) and scans ages 15 to 80, computing the reference BMR at each age. The age whose reference BMR is closest to your own BMR is reported as your metabolic age. Because the formula subtracts 5 kcal per year of age, a higher BMR maps to a younger metabolic age.

Example

A 30-year-old man, 178 cm and 75 kg:

BMR = 10 × 75 + 6.25 × 178 − 5 × 30 + 5 = 1717 kcal/day

Scanning the male reference body across ages, the closest matching reference BMR lands a few years below 30, so the tool reports a metabolic age slightly younger than his real age — a good result.

Your BMR vs reference	Metabolic age
Higher than your age’s average	Younger than you
About average	Close to your real age
Lower than your age’s average	Older than you

This is an informational estimate, not a clinical measure, and it runs entirely in your browser.