Find out how many calories you need each day to maintain, lose or gain weight, based on your body, age and activity level.
How many calories do I need?
Your calorie needs depend on your size, age, sex and how active you are. This calculator estimates your maintenance calories, then adjusts them for your goal:
- BMR from the Mifflin-St Jeor equation (calories at rest).
- Multiplied by your activity level to get maintenance calories (TDEE).
- Adjusted up or down by about 250 to 750 calories a day for gradual weight change.
Why 500 calories a day equals about 1 lb a week
A common rule of thumb is that about 3,500 calories equals one pound of body weight (about 7,700 per kilogram). A deficit of 500 calories a day adds up to 3,500 a week, so roughly 1 lb a week. In reality, weight loss usually slows over time as your body adapts, so treat this as a starting estimate.
Worked example
A 35-year-old woman who is 5 ft 5 in, weighs 154 lb and exercises moderately needs about 2,161 calories to maintain her weight. To lose about 1 lb a week, her target is about 1,661 calories a day.
Making a calorie target work
- Prioritize protein and vegetables, which help you feel full. See the macro calculator.
- Weigh yourself regularly and look at the trend over weeks, not single days.
- Do not go too low. Many guidelines suggest not going below about 1,200 calories a day for women or 1,500 for men without medical supervision.
- Keep moving. Strength training helps preserve muscle while losing fat.
Frequently asked questions
Why am I not losing weight at my calorie target?
Common reasons include underestimating portions, overestimating activity, and normal water weight changes. Track carefully for two weeks before adjusting.
Is it safe to lose more than 2 lb a week?
Faster loss is harder to sustain and can mean losing more muscle. Most guidelines recommend about 0.5 to 2 lb a week.
Related tools
These calculators give estimates for healthy adults based on published formulas. They are not medical advice. Talk to a doctor or registered dietitian before making major changes to your diet or exercise, especially if you are pregnant, under 18 or have a health condition.