BMR Calculator
Estimate your Basal Metabolic Rate — the calories your body burns at complete rest — with the formula and a worked example.
What BMR is
Your Basal Metabolic Rate is the energy your body uses just to keep you alive at complete rest — breathing, circulating blood, maintaining temperature, running your organs. It is the largest part of most people's daily energy use, before any activity is added. This estimates it from your height, weight, age and sex.
How it's estimated
The widely-used modern method is the Mifflin-St Jeor equation, which estimates BMR from your weight, height, age and sex — the factors that most affect resting metabolism. Metabolism generally runs higher with more body mass and tends to decline gradually with age.
Uses: weight, height, age, sexMore body mass -> higher BMROlder age -> gradually lower BMRAn estimate, not a precise figure
BMR from any equation is a population-based estimate, not a measured value — real resting metabolism varies between individuals with the same measurements, influenced by muscle mass, genetics, hormones and health, so your true figure could differ. It is a useful baseline for understanding energy needs, and it is the starting point for estimating total daily energy expenditure once activity is added. This is general information, not medical or nutrition advice; individual needs vary, and decisions about diet or health are best made with a qualified professional.
Questions & answers
What is BMR?
The calories your body burns at complete rest to keep you alive — breathing, circulation, organ function. It is the largest part of most people's daily energy use.
What affects BMR?
Mainly body mass, age and sex, plus muscle mass, genetics and health. More mass raises it; it tends to decline gradually with age.
Is the estimate exact?
No — it is a population-based estimate. Real resting metabolism varies between individuals with the same measurements, so treat it as a baseline.
Is this medical advice?
No — it is general information. Individual needs vary, and diet or health decisions are best made with a qualified professional.
Is my data uploaded?
No. The calculation happens in your browser.