How Many Calories Do I Need a Day? BMR & TDEE Explained

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Daily calories to maintain, lose or gain weight.Open tool →

BMR: your baseline

Basal metabolic rate is the energy your body uses just to stay alive. The Mifflin-St Jeor equation estimates it from weight, height, age and sex.

TDEE: what you actually burn

Multiply BMR by an activity factor – from 1.2 for a desk job with no exercise to 1.9 for hard daily training or physical work. Most people overestimate their activity; when in doubt, choose the lower option.

Adjusting for goals

About 500 calories below TDEE loses roughly half a kilo (a pound) a week; 500 above gains at a similar rate. Review after two weeks and adjust by 100-200 calories.

Limits of any calculator

Results are estimates within about 10%. They don't apply to children, pregnancy or medical conditions – ask a doctor or registered dietitian.

Frequently asked questions

Is 1,200 calories too low?

For most adults it's the bare minimum and hard to sustain; get medical advice before going that low.

Do I eat back exercise calories?

Your activity level already includes them.

Does it matter what I eat?

Yes – protein, fibre and whole foods make any target easier to stick to.