How this calorie calculator works
First, we estimate how many calories your body burns at rest. This is your BMR. We use the Mifflin-St Jeor equation, which looks at your sex, age, height, and weight. A 2005 review found it was the most likely of the common formulas to land within 10% of measured values in healthy adults.
Next, we multiply your BMR by your activity level. The factors range from 1.2 if you sit most of the day to 1.9 if you train hard every day or have a physical job. That gives your maintenance calories. Eat about this much and your weight should stay steady.
A calorie calculator to lose weight or gain
Below your maintenance number, you'll see a table of daily targets:
- Lose fat (our default): about 20% below maintenance.
- Lose 1 lb (0.45 kg) a week: about 500 calories below maintenance.
- Lose 0.5 lb (0.23 kg) a week: about 250 calories below maintenance.
- Maintain: your maintenance number.
- Gain 0.5 or 1 lb (0.23 or 0.45 kg) a week: about 250 or 500 calories above maintenance.
The weekly targets use the rough rule that 1 lb of body weight equals about 3,500 calories (7,700 per kg). We never go below 1,200 calories for women or 1,500 for men. If a target hits that floor, it's marked with a star.
What your result means
Your number is a good first guess, not a fact. Even the best formula can be off by 10% or more for some people. Weight loss also slows over time as your body adapts, so the weekly rates are best seen as a guide.
Pick a target, stick with it for 2 to 3 weeks, and weigh yourself a few times a week at the same time of day. If the scale isn't moving the way you expect, change your calories by 100 to 200 a day.
Tips to make your calories work harder
- Eat enough protein. It helps you feel full and keep muscle while you eat less. Our protein calculator gives you a daily target.
- Be honest about your activity. If you are torn between two levels, start with the lower one.
- Eating out? Our restaurant guides list calories and protein for popular orders.
Want a deeper look at picking a target? Read our guide on how many calories to eat to lose weight.
If you are pregnant, under 18, or have diabetes, kidney disease, or a history of eating disorders, talk to your doctor or a registered dietitian before cutting calories.