Calories Calculator

Daily calorie needs from the Mifflin-St Jeor equation and activity level.

Overview

Calculates Total Daily Energy Expenditure (TDEE) and target daily caloric intake for fat loss, muscle gain, or weight maintenance based on physical activity levels.

Formula & Calculation Method

TDEE = BMR × Activity Factor | BMR (Mifflin-St Jeor) = (10 × W) + (6.25 × H) - (5 × A) + s

W = Weight in kg, H = Height in cm, A = Age, s = Biological sex constant (+5 for males, -161 for females). Activity factors range from 1.2 (sedentary) to 1.9 (athlete).

Worked Example: 28-Year-Old Male (75 kg, 178 cm, Moderate Exercise)

Inputs: Age = 28 | Sex = Male | Weight = 75 kg | Height = 178 cm | Activity = Moderate (3-5 days/week)

  • BMR = (10 × 75) + (6.25 × 178) - (5 × 28) + 5 = 750 + 1112.5 - 140 + 5 = 1,727.5 kcal
  • Moderate Activity Factor = 1.55
  • Maintenance TDEE = 1,727.5 × 1.55 = 2,678 kcal/day
  • Target for steady 0.5 kg/week fat loss (500 kcal deficit) = 2,178 kcal/day

Summary: Basal BMR = 1,728 kcal | Maintenance TDEE = 2,678 kcal | Moderate Fat Loss Deficit = 2,178 kcal/day

Common Use Cases

  • Fat Loss Planning: Establish safe, sustainable 300 to 500 kcal daily deficits that prevent metabolic slowdown.
  • Lean Bulking: Calculate structured 250 to 400 kcal daily surpluses to promote hypertrophy while minimizing fat gain.
  • Dietary Tracking Calibration: Calibrate calorie intake targets on tracking apps like MyFitnessPal and Cronometer.

Frequently Asked Questions

What is the difference between BMR and TDEE?

BMR is calories burned at complete rest to keep organs functioning; TDEE is total calories burned including daily movement and exercise.

How large should my calorie deficit be for fat loss?

A moderate deficit of 15% to 20% below your maintenance TDEE (roughly 300 to 500 kcal/day) allows steady fat loss while preserving muscle.

Why do weight loss plateaus happen?

As you lose weight, your smaller body burns fewer calories, and metabolic adaptation lowers daily expenditure; recalculate your TDEE every 3-5 kg lost.

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