How Many Calories Do I Need? BMR and TDEE Explained
Your daily calorie needs have two parts: what your body burns at rest, and what activity adds on top. Both can be estimated in a minute — and both are estimates, so treat the result as a starting point.
Step 1: basal metabolic rate (BMR)
The Mifflin-St Jeor equation is considered one of the most accurate for adults:
BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age + 5 for men, − 161 for women.
Example: a 35-year-old woman, 65 kg, 165 cm → 650 + 1,031.25 − 175 − 161 = about 1,345 kcal/day.
Step 2: total daily energy expenditure (TDEE)
Multiply BMR by an activity factor:
| Activity | Factor |
|---|---|
| Sedentary | 1.2 |
| Light (1–3 days/week) | 1.375 |
| Moderate (3–5 days/week) | 1.55 |
| High (6–7 days/week) | 1.725 |
| Very high (physical job + training) | 1.9 |
With moderate activity, the example gives about 2,085 kcal/day to maintain weight. Most people overestimate their activity — when unsure, pick the lower level.
Gentle targets
The calorie calculator suggests about 15% below maintenance for gradual weight loss (here roughly 1,770 kcal) and about 10% above for gradual gain — and never suggests going below BMR. Bigger cuts are hard to sustain, cost muscle and aren't safe without professional supervision.
Adjust with real data
Equations can be off by about 10% for an individual. Track your weight for two or three weeks and adjust. Pregnancy, breastfeeding, medical conditions and a history of disordered eating call for individual guidance from a doctor or registered dietitian.
Related: check your BMI and your daily water needs.