THE NUMORIX GUIDE
How to use the Calorie Calculator
Last reviewed September 14, 2026
What this calculator does
The engine converts pounds to kilograms and inches to centimeters, calculates Mifflin-St Jeor BMR, and multiplies it by an activity factor: 1.
Formula and method
The engine converts pounds to kilograms and inches to centimeters, calculates Mifflin-St Jeor BMR, and multiplies it by an activity factor: 1.2 sedentary, 1.375 light, 1.55 moderate, 1.725 active, or 1.9 very active. It reports TDEE, TDEE - 500, and TDEE + 500, rounded to whole calories.
Variables and inputs
Enter age, the male or female equation option, weight in pounds, height in inches, and an activity level. The activity labels mean little or no exercise, 1-3 days/week, 3-5 days/week, 6-7 days/week, or twice-daily activity. Results are kcal/day.
Worked example
For the defaults of age 30, male, 180 lb, 70 in, and moderate activity: converted weight is 81.65 kg and height is 177.8 cm; BMR is about 1,783 kcal/day; TDEE is 1,782.7 * 1.55 = 2,763 kcal/day; the displayed loss, maintenance, and gain values are 2,263, 2,763, and 3,263 kcal/day.
How to interpret the result
TDEE is a planning estimate based on an activity multiplier. The loss and gain values are fixed 500-kcal adjustments, not individualized prescriptions. Actual maintenance can differ, so trends in weight, energy, hunger, and performance matter when reviewing the estimate.
Common mistakes to avoid
Use pounds and inches as labeled, and choose average weekly activity rather than your most active day. Do not treat the 500-kcal options as safe for every person or forget that a calorie estimate does not describe nutrient quality.
Assumptions and limitations
The model uses a constant activity multiplier and does not account for body composition, illness, pregnancy, breastfeeding, medications, adaptive changes, or the energy cost of specific activities. It can produce unrealistic targets at the edges of the input range and does not validate every field.