About the Metabolic Age Calculator
This tool estimates your basal metabolic rate, daily calorie needs, BMI, and an educational metabolic age comparison from your sex, age, height, weight, and activity level. It can help adults understand how their estimated resting energy use compares with a typical reference curve for people of the same sex and height.
How to use this calculator
- Select the sex used for the BMR equation.
- Enter your chronological age in years.
- Choose Metric or US / Imperial units, then enter your height and weight.
- Select the activity level that best matches your usual exercise or job demands.
- Click Calculate metabolic age to view your BMR, estimated daily needs, BMI, and metabolic age.
- Click Reset to restore the default values.
How it works
The calculator first converts your height and weight to metric units if needed. It then estimates basal metabolic rate using the Mifflin-St Jeor equation: BMR = 10 × weight in kg + 6.25 × height in cm − 5 × age + s, where s is +5 for male and −161 for female.
Estimated daily needs are calculated by multiplying BMR by the selected activity factor. BMI is calculated as weight in kilograms divided by height in meters squared.
To estimate metabolic age, the tool compares your estimated BMR with reference BMR values from ages 18 through 85 for your sex and height. Those reference values use a typical BMI curve by age to estimate reference weight, then apply the same BMR equation. The age with the closest reference BMR is reported as your metabolic age.
Results are educational estimates only and are not medical, nutrition, or weight-management advice. Metabolic age is not a diagnosis and may differ from results from bioimpedance scales, indirect calorimetry, or clinical testing.
Example calculation
For a 35-year-old male using metric units at 178 cm, 82 kg, and a moderate activity level of 1.55, the calculator estimates BMR as 10 × 82 + 6.25 × 178 − 5 × 35 + 5 = about 1,763 calories/day. Daily needs are about 1,763 × 1.55 = 2,733 calories/day, BMI is about 25.9, and the closest reference BMR comparison gives an estimated metabolic age of about 39 years.
Frequently asked questions
What does metabolic age mean?
Metabolic age is a comparison between your estimated BMR and a reference BMR for different ages. A lower value means your estimated resting calorie burn is closer to that of a younger reference age.
Is this calculator measuring my actual metabolism?
No. It estimates BMR from height, weight, age, and sex using an equation. Actual metabolism can vary with body composition, hormones, medications, illness, and training status.
Why does activity level not change metabolic age?
Activity level is used only to estimate daily calorie needs. Metabolic age is based on estimated resting metabolism, so it uses BMR rather than total daily expenditure.
What age range is used for the comparison?
The calculator compares your BMR with reference ages from 18 to 85. If the closest match is outside that range, the result is limited to the nearest age in that range.
Can I use this for medical or diet decisions?
Use it as an educational estimate only. For personalized health, nutrition, or weight-management guidance, consult a qualified healthcare professional.