How it works
Resting burn (BMR) uses the Mifflin-St Jeor equation: 10 × weight in kg + 6.25 × height in cm − 5 × age, then +5 for men or −161 for women. Total daily burn (TDEE) multiplies that by an activity factor from 1.2 (sedentary) to 1.9 (very active).
A pound of body fat is roughly 3,500 calories, so eating 500 fewer a day loses about a pound a week.
Worked example
A 30-year-old man, 180 cm, 80 kg: BMR = 800 + 1,125 − 150 + 5 = 1,780. With moderate activity (× 1.55): 2,759 calories a day to maintain, about 2,259 to lose a pound a week.
Frequently asked questions
How many calories should I eat a day?
It depends on size, age, sex and activity. Most adults fall between about 1,600 and 3,000; the calculator gives your own estimate.
What is TDEE?
Total Daily Energy Expenditure: everything you burn in a day, including exercise. Eat at your TDEE to stay the same weight.
Is Mifflin-St Jeor accurate?
It's one of the most accurate everyday formulas, usually within about 10% for most people.
How fast can I safely lose weight?
About 1 to 2 pounds a week is the usual recommendation.