This calorie calculator estimates basal metabolic rate and total daily energy expenditure using the Mifflin-St Jeor equation and an activity multiplier. It provides a starting estimate for nutrition planning rather than a precise measurement of metabolism.
How to use this calculator
Enter age, the sex coefficient used by the published equation, metric weight and height, and the activity level closest to your normal routine. BMR estimates resting energy use; maintenance calories multiply BMR by activity.
Formula & calculation method
BMR = 10W + 6.25H − 5A + s; maintenance = BMR × activity factorW is kilograms, H is centimeters, A is age in years, and s is +5 for the male equation or −161 for the female equation. Activity factors approximate total daily expenditure, including ordinary movement and exercise.
Worked example
A person with a calculated BMR of 1,500 and a lightly active factor of 1.375 has estimated maintenance needs of about 2,063 calories per day. Actual needs may vary from this population-based estimate.
Why this is useful
Showing BMR and maintenance separately clarifies the effect of the activity assumption. The calculator makes it easy to compare activity scenarios while keeping the underlying equation visible.
Limitations to keep in mind
Energy needs vary with body composition, health, pregnancy, medications, climate, and day-to-day activity. The tool is not designed for children or medical nutrition therapy. Consult a qualified professional for individualized guidance.
Frequently asked questions
Are these calories a weight-loss target?
No. The main result estimates maintenance needs. Changing energy intake for a health goal should account for individual circumstances and professional guidance where appropriate.
Why is activity included?
BMR covers resting functions only. The activity multiplier approximates additional energy used through daily movement and exercise.
How accurate is the estimate?
It is based on a widely used population equation, but individual measured expenditure can differ. Monitor real-world trends and adjust with appropriate guidance.