Calorie Calculator – Mifflin-St Jeor Daily Needs

The calculator first finds your basal metabolic rate with the Mifflin-St Jeor equation, which the Academy of Nutrition and Dietetics considers the most accurate predictive formula for most adults. Your BMR is then multiplied by an activity factor: 1.2 for sedentary, 1.375 for light exercise 1–3 days a week, 1.55 for moderate exercise 3–5 days, 1.725 for hard exercise 6–7 days, and 1.9 for physical jobs or twice-daily training. Worked example: a 30-year-old, 70 kg, 175 cm man has BMR = 10×70 + 6.25×175 − 150 + 5 = 1649 kcal; at the 1.55 multiplier his maintenance is about 2555 kcal/day. The results also show a 500 kcal deficit (≈0.45 kg per week) and a 1000 kcal deficit (≈0.9 kg per week).

1. 1

   Enter your metrics

   Provide age, sex, height in cm and weight in kg.

2. 2

   Compute Mifflin-St Jeor BMR

   The equation above returns your basal metabolic rate in kcal per day.

3. 3

   Apply activity multiplier

   Choose from 1.2 sedentary to 1.9 very active to get maintenance calories (TDEE).

4. 4

   Pick your goal

   Read maintenance, mild and aggressive deficit, or controlled surplus targets.

• 1

  Recalculate after every 4–5 kg of weight change; energy needs move with your weight.

• 2

  Track intake for two weeks and compare with the scale, then adjust by 100–200 kcal.

• 3

  Women should not eat below 1200 kcal and men below 1500 kcal without medical supervision.

• Overestimating activity level; most office workers belong to the 1.2–1.375 multipliers.

• Assuming the estimate is exact — predictive equations carry roughly ±10% error.

• Cutting calories below 1200 (women) or 1500 (men) and losing lean mass and micronutrients.