Your Total Daily Energy Expenditure is BMR multiplied by an activity factor. BMR uses the Mifflin–St Jeor equation by default — the most validated formula for the general population (±10% accuracy). When body fat % is provided, the calculator switches to Katch–McArdle, which is more accurate for athletes.
Fat loss: Eat 300–500 kcal below TDEE. Never go below your BMR for extended periods — this causes muscle loss and metabolic slowdown.
Muscle gain: Eat 200–350 kcal above TDEE (lean bulk). Hit your protein target every day to maximise muscle protein synthesis — use the protein calculator for exact daily targets.
Maintenance: Eat at TDEE. If weight drifts unexpectedly after 2 weeks, adjust by ±150 kcal and reassess.
Hit your protein target first, then fill remaining calories with carbs and fat to preference.
Frequently asked questions
What is the difference between BMR and TDEE?
BMR is calories burned at complete rest. TDEE is BMR × activity multiplier — your total daily burn including exercise. TDEE is typically 1.3–1.9× your BMR.
How many calories to lose 1 pound per week?
A 500 kcal/day deficit below your TDEE produces approximately 1 lb of fat loss per week, since 1 lb of fat ≈ 3,500 kcal.
Why does body fat % improve accuracy?
Standard formulas use total body weight. Muscle burns more calories at rest than fat. With body fat %, the Katch–McArdle formula isolates lean body mass for a more precise BMR estimate.
How often should I recalculate?
Every 4–8 weeks or after a 10 lb (4.5 kg) weight change. BMR decreases as you lose weight — not updating leads to stalled progress.