How to use the calorie calculator
- Enter your sex, age, height and weight (metric or imperial).
- Pick the activity level that best matches your week.
- Read your maintenance calories, plus targets to lose or gain weight at a steady pace.
How calorie needs are calculated
We use the Mifflin-St Jeor equation, the most accurate widely-used formula for resting metabolism (BMR), then multiply by an activity factor to get your TDEE.
women: BMR = 10·kg + 6.25·cm − 5·age − 161
TDEE = BMR × activity factor
A daily deficit of about 500 kcal loses roughly half a kilo (one pound) a week, because a pound of fat stores about 3,500 calories.
Activity factors
| Level | Factor |
|---|---|
| Sedentary (little/no exercise) | 1.20 |
| Lightly active (1–3 days) | 1.375 |
| Moderately active (3–5 days) | 1.55 |
| Very active (6–7 days) | 1.725 |
| Extra active (hard job/training) | 1.90 |
Frequently asked questions
Eat below your maintenance number. A 500-calorie daily deficit loses about half a kilo a week. Larger deficits work faster but are harder to sustain and risk losing muscle.
Bigger, younger, more muscular and more active people burn more. The formula reflects height, weight, age, sex and activity, so two people rarely match.
Base your intake on TDEE (maintenance), not BMR. Eating only at your BMR ignores the energy you burn moving around and usually creates too steep a deficit.
They’re different tools. BMI compares your weight to your height; calories estimate your energy needs. Check your BMI alongside this for a fuller picture.