How this calculator works
This calculator uses the Mifflin-St Jeor equation, a widely used formula for estimating resting energy expenditure in adults, and then multiplies the result by an activity factor:
- Males: (10 × weight in kg) + (6.25 × height in cm) − (5 × age) + 5
- Females: (10 × weight in kg) + (6.25 × height in cm) − (5 × age) − 161
Your inputs in pounds, feet and inches are converted to metric units behind the scenes. The result is an estimate of your maintenance calories, the amount that would keep your weight roughly stable.
Using your result for weight loss
A modest reduction from maintenance is a common starting point for gradual weight loss. The calculator shows estimates for reductions of about 250 and 500 calories per day. In practice, weight loss is rarely steady, because your body adapts and day-to-day water changes mask progress.
- Treat the number as a starting point. Track your weekly average weight for 2 to 4 weeks and adjust if needed.
- Focus on food quality as well as quantity. Our meal plans and recipes can help.
- Recalculate as your weight or activity changes.
The calculator won't display targets below about 1,200 calories a day for the female equation or 1,500 for the male equation, because intakes that low are generally recommended only with medical supervision.
Why your needs may differ
Equations estimate averages for groups of people. Your real needs can differ because of muscle mass, genetics, health conditions, medications, pregnancy, breastfeeding and how active you are outside of exercise. This calculator is intended for adults 18 and older and isn't suitable during pregnancy or for people with medical conditions that affect metabolism.
Important
This calculator provides a general estimate for educational purposes only. It isn't a diagnosis or a personalized medical recommendation. Talk with your doctor or a registered dietitian about your individual needs. See our medical disclaimer.