Daily calorie needs
An estimate of the energy your body uses at rest, and in total across a normal day.
Fill in your age, height and weight to see an estimate.
How this is worked out
The calculator uses the Mifflin-St Jeor equation, which estimates basal metabolic rate — the energy your body uses just staying alive, before you move at all. It is the equation most dietitians reach for, because it has held up better against measured values than the older Harris-Benedict formula.
That resting figure is then multiplied by an activity factor to give total daily energy expenditure.
Treat it as a starting point
Two people with identical height, weight, age and sex can differ by several hundred calories a day. The estimate does not account for body composition, thyroid function, some medicines, or genuine metabolic variation. Real-world activity is also the hardest thing to judge — most people overestimate how active they are.
The practical way to use it: take the number as a hypothesis, then adjust based on what actually happens to your weight over two or three weeks.
When to get proper advice
Please speak to a doctor or dietitian rather than relying on a calculator if you are pregnant or breastfeeding, under 18, managing diabetes or kidney disease, recovering from illness or surgery, or have a history of disordered eating. Very low calorie intakes in particular should only be undertaken with supervision.