Calorie Calculator
Free calorie calculator. Work out your basal metabolic rate and daily calorie needs with the Mifflin-St Jeor equation, plus targets for losing or gaining weight at a steady pace.
| To lose slowly | kcal per day | |
|---|---|---|
| To lose | kcal per day | |
| To gain slowly | kcal per day | |
| To gain | kcal per day |
What it does
Your basal metabolic rate is what your body burns doing nothing at all — breathing, pumping blood, keeping warm. Multiply it by how much you move and you get roughly what you spend in a day. It is an estimate about a population, not a measurement of you: two people with the same height, weight and age can differ by a few hundred calories. Use it as a starting point and adjust by what actually happens on the scale.
How to use it
- Choose your units, then enter sex, age, weight and height.
- Pick the activity level that matches a normal week, not your best one.
- Read the daily figure to maintain, and the targets above and below it.
The arithmetic runs in your browser. Nothing you type is sent anywhere and nothing is stored, so you can use these with real numbers.
Frequently asked questions
Which equation does this use?
Mifflin-St Jeor, which the Academy of Nutrition and Dietetics has recommended since 2005 because it predicts better than the older Harris-Benedict in today's population. Both numbers are shown, because people often arrive having seen the other one.
How accurate is it?
It is a population estimate with a typical error of around ten percent for any given person, and more for anyone very muscular or very lean — the formula knows nothing about body composition. Treat it as a starting point, not a prescription.
Why is 500 kcal the usual step?
Because roughly 7,700 kcal is a kilogram of body fat, so a deficit of 500 a day works out near half a kilo a week. The arithmetic is tidier than the body: the rate slows as you get lighter, since a smaller body burns less.
Can I just eat my basal rate?
It is rarely a good idea. Your basal rate is what you burn asleep; eating at that level while also moving leaves a large deficit, and sustained very low intakes cost muscle as well as fat. The page warns when a target falls below it.
Wikipedia — Basal metabolic rate
Wikipedia — Harris-Benedict equation
Wikipedia — Calorie
Wikipedia — Energy homeostasis