Free health tool
Calorie Needs Estimator
Daily energy needs are commonly estimated by calculating resting energy expenditure with the Mifflin–St Jeor equation and multiplying it by an activity factor. The result is an average-based estimate, and your real needs may be higher or lower.
Enter your details to estimate your daily energy needs. Not suitable during pregnancy or breastfeeding.
Calculated in your browser. Nothing you enter is sent or stored.
How this tool works
- 1Enter sex, age, height and weight (metric or imperial) and choose an activity level.
- 2Resting energy expenditure (REE) is estimated with the Mifflin–St Jeor equation.
- 3REE is multiplied by a standard activity factor (1.2 to 1.9) to estimate maintenance calories.
Formula: REE = 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5 (men) or − 161 (women)
Limitations
- For adults aged 18 and over. Not for pregnancy, breastfeeding, children, or people with medical conditions affecting metabolism.
- Equations predict averages; individual needs can differ substantially.
- Activity factors are broad categories and are easy to over-estimate.
- Use the number as a starting point and talk to a doctor or registered dietitian before major diet changes.