Calorie Calculator
Estimates only, using the Mifflin-St Jeor equation. Not medical advice.
The equation
Basal metabolic rate (BMR), the energy your body uses at rest, is estimated with the Mifflin-St Jeor equation:
- Men: 10 × weight (kg) + 6.25 × height (cm) − 5 × age + 5
- Women: 10 × weight (kg) + 6.25 × height (cm) − 5 × age − 161
BMR is then multiplied by an activity factor to estimate total daily energy expenditure (TDEE), roughly the calories that keep your weight steady.
Activity multipliers
| Activity level | Multiplier |
|---|---|
| Sedentary (little or no exercise) | × 1.2 |
| Light (exercise 1-3 days/week) | × 1.375 |
| Moderate (exercise 3-5 days/week) | × 1.55 |
| Active (exercise 6-7 days/week) | × 1.725 |
| Very active (hard exercise + physical job) | × 1.9 |
People most often overestimate this. "Moderate" means structured exercise most days, not a generally busy routine. If your weight trend doesn’t match the estimate after a few weeks of accurate tracking, try the level below.
Worked examples
| Person | BMR | Maintenance (light activity) |
|---|---|---|
| Woman, 35, 165 cm, 65 kg | 1,345 kcal | 1,849 kcal |
| Man, 35, 180 cm, 80 kg | 1,755 kcal | 2,413 kcal |
Weight loss and gain targets
The loss and gain figures use the common estimate that a kilogram of body fat stores about 7,700 kcal. A change of 0.25 kg a week works out to about 275 kcal a day, and 0.5 kg a week to about 550 kcal a day. In practice, weight change slows over time because your maintenance calories fall as your weight does, so recalculate after every few kilograms.
Limits
Equations like this predict the average person of your size, age, and sex. Individuals vary, and conditions such as thyroid disorders, some medications, pregnancy, and very high muscle mass can shift real needs. Talk to a doctor or a registered dietitian before making large changes to how you eat.
Source: Mifflin MD, St Jeor ST, et al. A new predictive equation for resting energy expenditure in healthy individuals. American Journal of Clinical Nutrition, 1990. For information only, not medical advice.