Calorie Calculator
This uses the Mifflin-St Jeor equation, which is the one most dietitians reach for. It gives what you burn in a day, then what to eat to move in either direction.
How the math works
Mifflin-St Jeor: BMR = 10 x weight in kg + 6.25 x height in cm - 5 x age, then +5 for men or -161 for women. Daily burn = BMR x an activity multiplier from 1.2 to 1.9. A 500 calorie daily change is about a pound a week, since a pound of fat holds roughly 3,500 calories.
Common questions
- How many calories should I eat a day?
- Start at the maintenance figure above and adjust from what the scale actually does over two or three weeks. Every equation is an estimate, and real metabolisms vary by a couple of hundred calories either way.
- Why Mifflin-St Jeor and not Harris-Benedict?
- Mifflin-St Jeor was published in 1990 against modern data and predicts resting rate more accurately for most people. Harris-Benedict dates from 1919 and tends to run high.
- Should I eat back calories burned in exercise?
- The activity multiplier already includes your usual training, so no, not on top. Watches also overestimate exercise burn substantially, often by a third or more.