Metabolic Age Calculator

Metabolic age is a simple idea: it turns your calorie burn into an age. Your body burns a certain number of calories at rest, called your basal metabolic rate, or BMR. If your BMR is high for your age, your metabolic age comes out younger than your real age. If it is low, it comes out older. Our free metabolic age calculator works out your BMR from your weight, height, age, and sex, then turns it into one metabolic age number, so you can see where you stand and track it over time.

This calculator uses the Mifflin-St Jeor equation, a widely used formula for estimating BMR that was published by Mifflin and colleagues in 1990. If you enter a body fat percentage, it uses the Katch-McArdle equation instead, which works from your lean body mass. Your BMR is then compared with the average BMR for each age group, and the age group whose average is closest to yours is your metabolic age. The result is an estimate, not a medical measurement. It is most useful for tracking changes in your own numbers over time, rather than for comparing yourself with other people. Our guide to BMR and TDEE explains the two numbers behind it.

A good metabolic age is the same as your real age or younger. A result a few years above your age is common and does not on its own mean you are unhealthy, because the comparison uses the average person your age and body size moves the result. What matters more is the direction the number moves when you change your habits, and how it sits alongside your BMI and your body fat percentage.

The most reliable way to improve your metabolic age is to build and keep muscle, because muscle burns more calories at rest than fat does. Strength training on two or more days a week, enough protein with your meals, 7 to 9 hours of sleep, and regular movement through the day all help. Walking more, taking the stairs, and standing up often during the day add up too. Our BMR calculator shows the calorie burn behind your result, and our TDEE calculator shows your daily calorie needs once activity is included. Recheck your metabolic age every few months, after your habits have had time to work, instead of every week.

This tool is for general information only. It does not diagnose anything, and it cannot replace a healthcare professional. If you have a health condition, take medication that affects your metabolism, or are pregnant, speak with your doctor before starting a new diet or exercise plan. Use the number as a starting point, pick one habit to improve first, and let the trend over months, not a single result, guide you.