Your daily calorie needs depend on your size, age, sex and how active you are. Enter your details to see an estimate for maintaining your weight, plus targets for slow weight loss or gain.
How this calculator works
First it estimates your resting metabolism (BMR), the energy your body uses at rest, with the Mifflin-St Jeor equation. Reviews comparing equations have found it the most accurate for most adults, usually within about 10% of measured values. It then multiplies your BMR by an activity factor, from 1.2 for little exercise to 1.9 for very hard training or physical work.
The weight-loss targets subtract 250 or 500 calories a day. These are rough guides: weight change slows over time as your body adapts, so check your progress every few weeks and adjust.
Who should be careful
- Very low-calorie diets should only be followed with medical supervision. The calculator won’t suggest targets below 1,200 calories for women or 1,500 for men.
- This calculator isn’t designed for pregnancy, breastfeeding, under-18s or people with a medical condition that affects weight.
Sources
- Mifflin MD, et al. A new predictive equation for resting energy expenditure in healthy individuals. Am J Clin Nutr. 1990;51(2):241-247.
- Frankenfield D, et al. Comparison of predictive equations for resting metabolic rate in healthy nonobese and obese adults: a systematic review. J Am Diet Assoc. 2005;105(5):775-789.