Calorie Calculator
How this calorie calculator works
This calculator estimates your daily calorie needs in three steps. First it computes your Basal Metabolic Rate (BMR) — the energy your body burns at complete rest — using the Mifflin-St Jeor equation. Then it multiplies by an activity factor to get your Total Daily Energy Expenditure (TDEE). Finally it adjusts that figure up or down depending on your goal, and splits the result into protein, carbohydrate, and fat targets.
The Mifflin-St Jeor equation
- Male: BMR = 10×weight + 6.25×height − 5×age + 5
- Female: BMR = 10×weight + 6.25×height − 5×age − 161
Weight is in kilograms, height in centimetres, and age in years.
Activity factors
- 1.2 — Sedentary (desk job, no exercise)
- 1.375 — Lightly active (light exercise 1–3 days/week)
- 1.55 — Moderately active (moderate exercise 3–5 days/week)
- 1.725 — Very active (hard exercise 6–7 days/week)
- 1.9 — Extra active (physical job or twice-daily training)
Weight goals
Roughly 7,700 kcal equals one kilogram of body fat. To lose 0.5 kg per week you need a daily deficit of about 3,850 ÷ 7 ≈ 550 kcal/day; to lose 0.25 kg/week the deficit is ~275 kcal/day. Gain goals add the same amounts symmetrically. "Maintain" leaves the TDEE unchanged.
Macronutrient split
Macro targets are calculated from your maintenance TDEE using a balanced 30/40/30 split:
- Protein — 30% at 4 kcal/g (builds and repairs muscle)
- Carbs — 40% at 4 kcal/g (primary fuel for activity)
- Fat — 30% at 9 kcal/g (hormones, absorption, satiety)
These are starting points, not gospel. If you lift weights heavily, consider raising protein toward 2 g/kg of body weight. If you feel sluggish on higher carbs, shift some grams toward fat. Track your results for two to three weeks and adjust.