Health
Daily calorie calculator
Sex, age, height, weight and activity: see how many calories your body burns at rest and on a typical day, and how many you need to maintain, lose or gain weight.
Basal metabolic rate and daily calories
Basal metabolic rate is the energy your body uses at rest to breathe, keep the heart beating and hold its temperature. The Mifflin–St Jeor equation (1990) is today the most widely used estimate: for a 30-year-old man of 80 kg and 180 cm it gives about 1780 kcal a day.
Daily needs come from multiplying the basal rate by an activity factor, from 1.2 for sedentary people to 1.9 for very heavy physical work. That is the intake that keeps weight stable.
To lose about half a kilo (a pound) a week, people typically eat around 500 kcal a day less; to gain, 500 more. The body adapts, so the figures are worth recalculating as weight changes.
Common mistakes
- Overstating activity: an hour at the gym on an otherwise seated day is light or moderate, not active.
- Eating far below the basal rate to lose weight faster.
- Counting activity twice, adding a fitness tracker's calories on top of a high factor.
Frequently asked questions
How many calories do I need a day?
On average about 2000–2500 kcal for men and 1600–2000 for women, but it depends a lot on age, weight, height and activity, which is why it is worth calculating.
What is the difference between BMR and daily calories?
BMR is what you burn at complete rest; daily calories add everything you do during the day, from walking to sport.
How big a deficit should I aim for?
About 500 kcal a day leads on average to half a kilo (about a pound) a week. Larger deficits should be agreed with a professional.
How this calculation works
Mifflin–St Jeor: men 10·weight + 6.25·height − 5·age + 5; women 10·weight + 6.25·height − 5·age − 161 (weight in kg, height in cm). Daily calories = BMR × 1.2 / 1.375 / 1.55 / 1.725 / 1.9 by activity. Targets: ± 500 kcal, never below 1500 kcal for men and 1200 for women.
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