BMR Calculator
Estimated adult resting energy expenditure with a transparent formula comparison
years
For adults age 18 and older. The original Mifflin study included people aged 19 to 78, so estimates outside that range are less certain. cm
kg
ft
in
lb
%
Estimated resting energy expenditure using Mifflin–St Jeor
This result is an estimate, not a direct metabolic measurement.
Physical activity and daily movement are not included. Calculate total calorie needs →
Compare additional equations
Revised Harris–Benedict
Katch–McArdle equation
Equation sources: Mifflin–St Jeor · Harris–Benedict
Frequently Asked Questions
What Is BMR?
Your Basal Metabolic Rate (BMR) is the number of calories your body needs to maintain basic functions at complete rest — breathing, circulation, and cell production. It forms the baseline for calculating your total daily energy expenditure (TDEE).
Which Formula Should I Use?
The calculator uses Mifflin–St Jeor for the primary estimate and Harris–Benedict as an additional comparison. If body fat percentage is known, it also shows Katch–McArdle based on estimated lean mass. Every result remains an approximation.