Question 1

What is BMR?

Accepted Answer

Basal metabolic rate is roughly the number of calories your body burns at complete rest just to keep vital functions running — breathing, circulation, and cell repair. It does not include any calories burned through movement or digestion.

Question 2

What is the difference between BMR and TDEE?

Accepted Answer

Total daily energy expenditure (TDEE) takes BMR and multiplies it by an activity factor to account for exercise and daily movement, giving a more realistic estimate of how many calories you burn — and need to eat to maintain your current weight — across a full day.

Question 3

Why does this use the Mifflin-St Jeor equation?

Accepted Answer

Mifflin-St Jeor is widely regarded by dietitians as more accurate for most modern adults than older formulas like Harris-Benedict, which was derived from a smaller, less representative population nearly a century ago.

Question 4

Is a 500-calorie deficit always the right way to lose weight?

Accepted Answer

A roughly 500 kcal/day deficit is a commonly cited rule of thumb for about 0.5 kg of weight loss per week, but individual results vary with metabolism, muscle mass, sleep, and other factors. Large or prolonged deficits carry more risk of muscle loss, nutrient deficiency, and metabolic slowdown, so bigger changes are best guided by a registered dietitian.

Lose ~0.5 kg/week	1,496 kcal/day
Lose ~0.25 kg/week	1,746 kcal/day
Maintain weight	1,996 kcal/day
Gain ~0.25 kg/week	2,246 kcal/day

BMR & Daily Calorie Calculator

How BMR is calculated

Common questions