Health and fitness tools
BMR Calculator
Estimate your basal metabolic rate (BMR) from age, sex, height, and weight locally in your browser.
Estimate the energy your body uses at rest.
Enter your age, sex, height, and weight in metric or imperial units. The calculator uses the Mifflin–St Jeor equation to estimate basal metabolic rate: the calories your body uses each day at rest. This is a general estimate, not medical advice; individual needs can differ because of health conditions, pregnancy, body composition, medicines, and activity. Your values are calculated locally and are not uploaded or stored.
Frequently Asked Questions
Everything you need to know about this tool, how it works, and privacy.
What is this BMR estimate based on?
This calculator uses the Mifflin–St Jeor equation, which estimates basal metabolic rate from age, sex, height, and weight. It estimates the energy your body uses each day at rest.
Which inputs do I need?
Enter your age, sex, height, and weight. You can choose metric units (centimetres and kilograms) or imperial units (inches and pounds).
What is the difference between BMR and TDEE?
BMR estimates energy used at rest. Total daily energy expenditure (TDEE) adds energy used for daily movement, exercise, and digestion, so it is usually higher than BMR.
What are this calculator’s limitations?
BMR is a general estimate, not medical advice or a diagnosis. Individual energy needs can differ because of health conditions, pregnancy, body composition, medicines, age, and activity. Discuss personal nutrition or health questions with a qualified healthcare professional.
Do my details stay private?
Yes. The calculation runs locally in your browser. CodeASystem does not upload or store the age, sex, height, or weight you enter.