BMR Calculator
Estimate resting energy use with the Mifflin–St Jeor equation and see the assumptions behind the result.
Calculate your estimate
What this tool tells you
This calculator estimates resting energy expenditure, often called BMR in everyday use. It represents approximate energy use at rest, not a recommended calorie intake.
How the estimate works
Mifflin–St Jeor: 10 × weight (kg) + 6.25 × height (cm) − 5 × age (years) + 5 for the original male coefficient or −161 for the original female coefficient. The equation was developed to predict resting energy expenditure; strictly measured basal metabolic rate is a different laboratory measure.
Important limitations
Prediction equations cannot capture body composition, illness, medications, pregnancy, or all individual differences. The original study included adults aged 19–78, so outputs outside that age range are extrapolations. The equation has only male and female coefficients. If neither coefficient fits your situation, seek individualized guidance rather than relying on this estimate.
Frequently asked questions
Is this my daily calorie target?
No. It estimates resting energy use. Total daily energy use also includes movement and other factors.
Why does the calculator ask for an equation coefficient?
The original Mifflin–St Jeor equation uses two sex-specific constants. They are limitations of the published model, not a statement about gender identity.
Why might my actual needs differ?
Age, body composition, health conditions, and daily activity can affect energy use beyond what a simple equation captures.
Understand your energy estimate
See how resting energy and daily activity relate, and why the output is an estimate rather than a personal intake target.