How Many Calories Do You Need? A Practical Guide
Your body uses energy all day, even at rest, to breathe, keep your heart beating and maintain body temperature. On top of that, every movement and workout burns extra energy. This calculator estimates both parts to give your approximate daily calorie needs.
Step 1: Basal Metabolic Rate (BMR)
BMR is the energy your body needs at complete rest. The calculator uses the Mifflin-St Jeor equation, which research has found to be one of the more reliable formulas for most adults:
Women: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age − 161
Step 2: Total Daily Energy Expenditure (TDEE)
BMR is multiplied by an activity factor to estimate the calories you burn on a typical day:
| Activity level | Multiplier |
|---|---|
| Sedentary (desk job, little exercise) | 1.2 |
| Light (exercise 1–3 days a week) | 1.375 |
| Moderate (exercise 3–5 days a week) | 1.55 |
| Active (hard exercise 6–7 days a week) | 1.725 |
| Very active (physical job or twice-daily training) | 1.9 |
Most people overestimate their activity. If you're unsure, choose the lower option.
Gradual, sustainable changes
The table shows estimated calories for maintaining your weight and for gradual changes of about 0.25–0.5 kg (0.5–1 lb) per week. Slow changes are easier to sustain and help protect muscle and overall health. The calculator doesn't suggest very low intakes; if a target would fall below commonly recommended minimums, it is marked as not recommended without medical supervision.
Why your real needs may differ
- Formulas estimate averages; individual metabolism can vary.
- Muscle mass, genetics, sleep, stress, medications and health conditions all play a part.
- Your needs change as your weight, age and activity change, so recalculate from time to time.
Quality matters as much as quantity: a balanced diet with plenty of vegetables, fruit, whole grains, protein and water supports energy and health. For personal advice, especially if you have a medical condition, speak to a doctor or registered dietitian.