Methodology

Basal metabolic rate: Mifflin-St Jeor

Our BMR calculator uses the Mifflin-St Jeor equation, which estimates resting energy expenditure from weight, height, age and sex.

Male:   BMR = (10 x weight_kg) + (6.25 x height_cm) - (5 x age) + 5
Female: BMR = (10 x weight_kg) + (6.25 x height_cm) - (5 x age) - 161

The equation is defined in metric units. When you use US customary inputs, we convert them before applying the equation and never round intermediate values.

Unit conversions

• 1 inch = 2.54 centimeters (height in feet is converted to inches first)
• 1 pound = 0.45359237 kilograms

Total daily energy expenditure

TDEE is estimated by multiplying BMR by a standard activity factor. These multipliers are conventional planning figures, not measured values for any individual.

• Sedentary — x1.2 (Desk job, little or no exercise)
• Lightly Active — x1.375 (Light exercise 1-3 days per week)
• Moderately Active — x1.55 (Moderate exercise 3-5 days per week)
• Very Active — x1.725 (Hard exercise 6-7 days per week)
• Extremely Active — x1.9 (Physical job or twice-daily training)

Input validation

Inputs are rejected before any calculation runs if they are empty, non-numeric, zero, negative, or outside plausible adult ranges: age 15-100 years, height 100-250 cm (about 3 ft 3 in to 8 ft 2 in) and weight 25-350 kg (about 55-771 lb). The calculator will never display NaN, Infinity, undefined or null; an explanatory message is shown instead.

Rounding

Results are rounded to the nearest whole calorie for display only. Precision beyond whole calories would imply an accuracy these estimates do not have.

Limitations

Population equations do not account for individual body composition, thyroid function, medication, pregnancy, illness or training history. Treat every figure on this site as an informational estimate rather than a prescription, and speak with a qualified healthcare professional about your own calorie needs.