Calorie Calculator

Estimate your daily calorie needs from your BMR, activity level, and goal.

How the calculator works

The calculation runs in three steps. Step one, BMR: men get (10 × weight in kg) + (6.25 × height in cm) − (5 × age) + 5, and women get the same core terms but end with − 161, reflecting the lower average metabolic rate of female bodies at the same size. Step two, activity: the BMR is multiplied by one of five standard factors — 1.20 sedentary, 1.375 lightly active, 1.55 moderately active, 1.725 very active, and 1.90 extra active — because every movement on top of resting metabolism burns additional energy. Step three, goal: the maintenance result is kept as-is for maintaining weight, reduced by 500 kcal to lose roughly half a kilogram per week, or increased by 300 kcal to gain weight at a measured pace that limits fat accumulation.

Formula

BMR = (10 × weight kg) + (6.25 × height cm) − (5 × age) + 5 (men) | − 161 (women)
TDEE = BMR × activity multiplier
Target = TDEE − 500 (lose) | TDEE (maintain) | TDEE + 300 (gain)

Where:

  • weight — body mass in kilograms
  • height — stature in centimeters
  • activity multiplier — 1.20 / 1.375 / 1.55 / 1.725 / 1.90 by activity level
  • ±500 / +300 kcal — the daily adjustment for losing or gaining weight

Example

Take a 30-year-old man weighing 70 kg at 175 cm who trains three days a week. His BMR is (10 × 70) + (6.25 × 175) − (5 × 30) + 5 = 1,649 calories. With a moderately active multiplier of 1.55, his maintenance works out at about 2,556 calories a day. Choosing “Lose weight” sets his target near 2,056 calories, a deficit of 500 that over a week adds up to roughly half a kilogram of body mass; “Gain weight” would instead put him near 2,856.

Frequently Asked Questions

How accurate is the Mifflin-St Jeor equation?
For most adults it predicts measured resting metabolism within about 10 percent, which is better than older formulas such as Harris-Benedict. Very muscular or very high-body-fat individuals can fall further from the estimate, because body composition changes how many calories tissue burns at rest.
Should I eat back the calories I burn exercising?
No — that is what the activity multiplier already accounts for. Choosing “moderately active” raises your maintenance calories to cover three to five training days a week, so adding exercise calories again would double-count them and quietly erase your intended deficit.
Why is the deficit 500 but the surplus only 300?
Fat tissue yields about 7,700 kcal per kilogram, so 500 kcal daily is a practical, sustainable route to losing roughly half a kilogram a week. Surplus calories, by contrast, build muscle only slowly, so a larger surplus mostly adds fat — 300 kcal is a common starting point for lean gaining.
How often should I recalculate my calories?
Whenever your weight, activity, or goal changes meaningfully — typically every 4–6 weeks during a diet. Losing 5 kg lowers your BMR and daily needs, so the target that worked at the start eventually becomes your new maintenance level.