How many calories do you need?
Your body burns energy all day: to keep your heart beating and organs working (your basal metabolic rate, or BMR), to digest food, and to move. The total is called your total daily energy expenditure (TDEE). Eating roughly your TDEE keeps your weight stable; eating less leads to weight loss and eating more leads to gain.
This calculator estimates BMR with the Mifflin–St Jeor equation, which studies have found to be the most accurate of the common prediction equations for healthy adults, then multiplies it by an activity factor to estimate TDEE.
How to use the calorie calculator
- Choose metric or imperial units and select your sex.
- Enter your age, weight and height.
- Pick the activity level that best matches a typical week. If in doubt, choose the lower option; most people overestimate.
- Read your maintenance calories and the targets for gentle or faster weight loss and gain.
The Mifflin–St Jeor equation
Men: BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age + 5
Women: BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age − 161
| Activity level | Multiply BMR by |
|---|---|
| Sedentary | 1.2 |
| Light | 1.375 |
| Moderate | 1.55 |
| Active | 1.725 |
| Very active | 1.9 |
A deficit of about 500 kcal a day is commonly used to lose roughly 0.5 kg (1 lb) a week, since a kilogram of body fat stores roughly 7,700 kcal. Real-world results vary as your body adapts.
Example
A 30-year-old man who weighs 80 kg, is 180 cm tall and exercises 3–5 days a week has a BMR of 10 × 80 + 6.25 × 180 − 5 × 30 + 5 = 1,780 kcal. Multiplying by 1.55 gives a maintenance level of about 2,759 kcal a day. To lose about half a kilogram a week, he would aim for roughly 2,259 kcal.
More worked examples
Light activity: a 35-year-old woman who weighs 68 kg, is 165 cm tall and exercises 1–3 days a week has a BMR of about 1,375 kcal and needs about 1,891 kcal a day to maintain her weight.
Common mistakes to avoid
- Overestimating activity. Most people choose a level that is too high; start one level lower and adjust after a few weeks.
- Cutting calories too far. Very low intakes are hard to sustain and can lack nutrients.
- Never recalculating. Your needs fall as you lose weight. Check your BMI and recalculate every few kilograms.
Sources and methodology
The calculations on this page follow these published standards and references. The code is covered by automated tests against known values.