THE NUMORIX GUIDE
How to use the Calorie Needs Calculator
Last reviewed September 14, 2026
What this calculator does
The engine applies Mifflin-St Jeor in metric units: 10 * weightKg + 6.
Formula and method
The engine applies Mifflin-St Jeor in metric units: 10 * weightKg + 6.25 * heightCm - 5 * age + 5 for male, or -161 for female. It multiplies BMR by 1.2, 1.375, 1.55, 1.725, or 1.9 for sedentary through very active, rounds TDEE, and adds or subtracts 500 kcal/day for gain or loss displays.
Variables and inputs
Enter age in years, gender, weight in kilograms, height in centimeters, and one of the UI activity values: sedentary, light, moderate, active, or very active. The engine's last key is `veryActive`; an unknown key silently falls back to the moderate factor of 1.55.
Worked example
For age 30, male, 70 kg, 175 cm, and moderate activity: BMR = 10 * 70 + 6.25 * 175 - 5 * 30 + 5 = 1,648.75, rounded to 1,649; TDEE = 1,648.75 * 1.55 = 2,555.56, rounded to 2,556; loss and gain displays are 2,056 and 3,056 kcal/day.
How to interpret the result
TDEE is a model-based estimate of average daily energy use. The loss, maintenance, and gain rows are scenario targets around that estimate, not clinical prescriptions or guarantees of a specific weight change.
Common mistakes to avoid
Use kg and cm as labeled, distinguish the moderate and active options, and do not confuse BMR with a full-day energy need. Keep the activity selection aligned with a typical week rather than a single workout.
Assumptions and limitations
The route has no input validation for age, height, weight, or percentage-like activity values and silently uses moderate activity for an unrecognized key. It does not account for body composition, illness, pregnancy, breastfeeding, medications, or adaptive changes.