How this calorie calculator works
First it estimates your Basal Metabolic Rate (BMR), the energy your body burns at complete rest. It uses the Mifflin-St Jeor equation, which studies have found to be the most accurate everyday formula for most adults.
Then it multiplies your BMR by an activity factor to get your maintenance calories, also called TDEE (Total Daily Energy Expenditure).
| Activity level | Multiplier |
|---|---|
| Sedentary (little or no exercise) | 1.2 |
| Light (1–3 days a week) | 1.375 |
| Moderate (3–5 days a week) | 1.55 |
| Active (6–7 days a week) | 1.725 |
| Very active (physical job plus training) | 1.9 |
To lose or gain weight, the calculator adds or removes calories. One pound of body fat holds roughly 3,500 kcal, so losing 1 lb a week needs a deficit of about 500 kcal a day.
Want the full picture? Read how many calories to eat to lose weight, or split your calories into protein, carbs and fat with the macro calculator.
How to use the calorie calculator
- Choose lb or kg in the "About you" heading. The calculator starts in US units (pounds, feet and inches).
- Enter your sex, age, weight and height. These set your basal metabolic rate.
- Pick your activity level. Count both workouts and your job. A desk job with three gym sessions a week is usually "Light" or "Moderate."
- Choose a goal: lose 0.5, 1 or 2 lb a week, maintain, or gain 0.5 or 1 lb a week.
- Read your result. The big number is your daily calorie target. The table shows the calories for every other goal, so you can compare.
Example: daily calories for a 180 lb man
A 30-year-old man who is 5 ft 9 in, weighs 180 lb and exercises 3–5 days a week has a BMR of about 1,767 calories and maintenance calories (TDEE) of about 2,739. To lose 1 lb a week he would eat about 2,240 calories a day; to lose 2 lb a week, about 1,741. To gain 0.5 lb a week while lifting, about 2,990.
How many calories a day do I need?
The Dietary Guidelines for Americans estimate that adult women need about 1,600–2,400 calories a day and adult men about 2,000–3,000, depending on age and activity. Your personal number can be higher or lower, which is why a calculator that uses your own height, weight and activity is more useful than a general chart.
Tips for accurate results
- Weigh yourself in the morning, after using the bathroom, before eating.
- Don't overestimate your activity. When in doubt, choose the lower level.
- Recalculate every 10 lb, because your calorie needs fall as you lose weight.
- Test the number: eat at your target for 2–3 weeks and compare your average weight. Adjust by 100–200 calories if needed.
What to do with your number
Split your calories into protein, carbs and fat with the macro calculator, see your finish date with the calorie deficit calculator, and read our in-depth guides: calorie deficit explained and how many calories you burn a day.
Frequently asked questions
How many calories should I eat to lose weight?
Start about 500 kcal below your maintenance calories. For most people that means losing around 1 lb (0.45 kg) a week, a pace that is easier to keep up and protects muscle.
Is 1,200 calories a day enough?
1,200 kcal is often cited as a floor for women and 1,500 kcal for men. Eating less than that for long periods makes it hard to get enough nutrients. Check with a doctor or dietitian before going lower.
How many calories are in a gram of fat, protein and carbs?
Fat has 9 calories per gram. Protein and carbohydrates each have 4 calories per gram. Alcohol has 7 calories per gram.
What is the difference between BMR and TDEE?
BMR is what you burn lying still all day. TDEE adds everything else: walking, working, exercise and digesting food. TDEE is the number to eat at if you want to keep your weight the same.
How accurate is this calculator?
Formulas like this are usually within about 10% for most people. Use the result as a starting point, track your weight for 2–3 weeks, and adjust by 100–200 kcal if you are not moving toward your goal.
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