BMR (Mifflin-St Jeor) and total daily energy expenditure, based on your activity level.
—BMR (calories/day)
—TDEE (maintenance)
Fat loss (-20%)—
Mild cut (-500 cal)—
Maintenance—
Lean bulk (+300 cal)—
How it works
BMR is calculated with the Mifflin-St Jeor equation — 10 × weight(kg) + 6.25 × height(cm) − 5 × age, plus 5 for men or minus 161 for women — then multiplied by an activity factor (from 1.2 for sedentary up to 1.9 for very active) to get TDEE. Switching between metric and imperial converts your entered numbers on the spot using fixed factors (1 kg = 2.20462 lb, 1 in = 2.54 cm) rather than clearing the fields.
FAQ
Why does the formula treat men and women differently?
Mifflin-St Jeor adds +5 for men and −161 for women as a correction for typically different average body composition — it's an equation fitted to population data, not a physical law, so any one person's actual metabolism can vary from it.
Do the cut and bulk targets account for how much of the change is muscle versus fat?
No — they're just fixed percentage or calorie offsets from your TDEE figure. How much of a deficit or surplus ends up as fat versus muscle depends on training and protein intake, which this calculator doesn't model.
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