How to use this BMR calculator
- Select the male or female equation used for the calculation.
- Enter an adult age, current body weight and standing height.
- Select Calculate. Read the result as estimated resting expenditure, not a complete daily food target.
The formula and method
Although commonly searched as a BMR calculator, this tool implements an equation for resting energy expenditure (REE). Basal metabolic rate is measured under stricter conditions; a web formula does not perform that measurement.
Male equation: 10 × weight (kg) + 6.25 × height (cm) − 5 × age (years) + 5. Female equation: 10 × weight (kg) + 6.25 × height (cm) − 5 × age (years) − 161.
The original Mifflin study derived a prediction from measured resting expenditure. The result is a population-based estimate, not a personalized metabolism test. Use the TDEE tool if you want to add an activity assumption.
Worked example
For a 30-year-old female weighing 80 kg at 180 cm: BMR = (10 × 80) + (6.25 × 180) - (5 × 30) - 161 = 800 + 1125 - 150 - 161 = 1,614 kcal/day. For a male of identical age and size: BMR = 800 + 1125 - 150 + 5 = 1,780 kcal/day.
Understanding the estimate
- The equation uses age, weight, height and sex constants; it does not directly measure body composition or your metabolism.
- Individual measured expenditure can differ from the formula result.
- The displayed value does not establish a safe minimum intake or account for your full day of activity.
Frequently asked questions
Is BMR the same as maintenance calories?
No. Maintenance expenditure includes the rest of your day. This result estimates resting expenditure only.
Why are there two sex equations?
The published simplified model uses two constants, +5 and −161. Selecting one applies that model; it cannot account for every individual difference.
Can a calculator measure my metabolism?
No. This is an estimate based on input measurements. Direct assessment of resting expenditure uses a different measurement process.