How many calories do you need?
Your daily calorie need, often called TDEE (total daily energy expenditure), is your basal metabolic rate multiplied by an activity factor. The factor covers everything beyond rest: walking, work, exercise and digesting food.
| Activity level | Factor | Typical day |
|---|---|---|
| Sedentary | 1.2 | Desk job, little exercise |
| Light | 1.375 | Exercise 1–3 days a week |
| Moderate | 1.55 | Exercise 3–5 days a week |
| Active | 1.725 | Hard exercise 6–7 days a week |
| Very active | 1.9 | Physical job plus training |
Worked example
A 30-year-old woman, 5 ft 5 in and 132 lb, who exercises 3–5 days a week: BMR 1,320 kcal × 1.55 = about 2,046 kcal a day to maintain her weight. Eating about 1,546 kcal a day (500 less) would typically lead to a loss of roughly 1 lb a week at first.
Using the numbers
These are estimates; your real needs can differ by 10% or more. Track your weight for two to three weeks and adjust. The Dietary Guidelines for Americans suggest most adult women need 1,600–2,400 kcal and men 2,000–3,000 kcal a day depending on activity. Very low-calorie diets should be supervised by a health professional.
How this works
The page calculates your basal metabolic rate with the Mifflin–St Jeor equation, then multiplies it by the factor for your activity level to get maintenance calories. Weight-loss targets subtract 250 or 500 kcal a day and the gain target adds 500. Results are rounded to whole calories. Everything is calculated in your browser.
Frequently asked
How many calories should I eat to lose weight?
About 500 fewer than your maintenance calories for roughly 1 lb (0.45 kg) a week at first.
What is TDEE?
Total daily energy expenditure: your BMR plus the energy used by activity and digestion.
Which activity level should I choose?
Be conservative. Most people with desk jobs who exercise a few times a week are light or moderate.
Why am I not losing weight at the predicted rate?
Metabolism adapts as you lose weight, and tracking is imprecise; recalculate as your weight changes.
Sources
- Mifflin et al. (1990) — A new predictive equation for resting energy expenditure in healthy individuals, Am J Clin Nutr
- FAO/WHO/UNU (2001) — Human energy requirements: physical activity levels
- Wikipedia — Harris–Benedict equation
Reviewed Oct 17, 2026 · test vectors fixtures/calculators/health/calorie-calculator/