How many calories you need depends on how much energy your body burns, and that is different for everyone. This calorie calculator estimates your basal metabolic rate (BMR) and your total daily energy expenditure (TDEE), the number of calories that keeps your weight stable. It then shows how many calories to eat to lose about 0.5, 1 or 2 lb a week, or to gain weight.
Quick answer: Maintenance calories = BMR × activity factor. Men: BMR = 10 × kg + 6.25 × cm − 5 × age + 5. Women: the same, minus 161 instead of plus 5. A 30-year-old man (5 ft 10 in, 180 lb, moderately active) maintains on about 2,763 calories a day; eating 2,263 would lose about 1 lb a week.
How to use the calorie calculator
- Choose U.S. units (feet, inches, pounds) or metric (cm, kg).
- Enter your sex, age, height and weight.
- Pick the activity level that matches a typical week.
- Press Calculate to see your maintenance calories, BMR and targets for losing or gaining weight, plus your calories at every activity level.
How many calories do I burn a day?
The calculator uses the Mifflin-St Jeor equation for BMR and multiplies it by an activity factor:
| Activity level | Description | Factor |
|---|---|---|
| Sedentary | Desk job, little or no exercise | 1.2 |
| Lightly active | Exercise 1–3 days a week | 1.375 |
| Moderately active | Exercise 3–5 days a week | 1.55 |
| Very active | Hard exercise 6–7 days a week | 1.725 |
| Extra active | Physical job or training twice a day | 1.9 |
How many calories to lose weight?
| Goal | Daily calories | Approximate change |
|---|---|---|
| Mild weight loss | Maintenance − 250 | −0.5 lb per week |
| Weight loss | Maintenance − 500 | −1 lb per week |
| Extreme weight loss | Maintenance − 1,000 | −2 lb per week |
| Weight gain | Maintenance + 500 | +1 lb per week |
Targets never go below 1,200 calories for women or 1,500 for men, the usual minimums without medical supervision.
Calorie calculation examples
Example 1: man, 30, 5 ft 10 in, 180 lb, moderately active
- Weight 180 lb = 81.6 kg, height 70 in = 177.8 cm
- BMR = 10 × 81.6 + 6.25 × 177.8 − 5 × 30 + 5 = 1,783 calories
- Maintenance = 1,783 × 1.55 = 2,763 calories
- To lose 1 lb a week: 2,763 − 500 = 2,263 calories
Example 2: woman, 35, 165 cm, 65 kg, sedentary
- BMR = 650 + 1,031.25 − 175 − 161 = 1,345 calories
- Maintenance = 1,345 × 1.2 = 1,614 calories
- A 1,000-calorie deficit would fall below 1,200, so the calculator caps the target at 1,200 calories and suggests a slower pace.
How to read your results
- Maintenance is a starting point. Track your weight for 2–3 weeks at that intake. If it moves, adjust by 100–200 calories.
- Protein matters while you diet. Eating enough protein and doing strength training help you keep muscle while losing fat.
- Check your weight category. Use the BMI calculator to see where your weight sits for your height, and the body fat calculator to estimate how much of it is fat.
- Switching units? The weight converter turns pounds into kilograms and back.
Common mistakes
- Overestimating activity. A daily walk usually counts as lightly active, not very active.
- Eating back exercise calories twice. The activity factor already includes your planned workouts.
- Cutting too fast. Very large deficits cost muscle and are hard to keep up.
- Never recalculating. As you lose weight, your maintenance calories drop too.
This calculator gives estimates for healthy adults and is not medical advice. If you are pregnant, breastfeeding, under 18 or have a medical condition, ask your doctor or a registered dietitian for a personal plan.
Frequently asked questions
How many calories should I eat a day?
It depends on your size, age, sex and activity. As a rough guide, the Dietary Guidelines for Americans estimate 1,600–2,400 calories a day for adult women and 2,000–3,000 for adult men. For a personal number, multiply your BMR by your activity factor; this calculator does both steps for you.
How many calories should I eat to lose weight?
Eat about 500 calories a day less than your maintenance calories to lose roughly 1 lb a week, or 250 less for about 0.5 lb a week. A 30-year-old man who is 5 ft 10 in, 180 lb and moderately active maintains on about 2,763 calories, so about 2,263 a day would mean losing roughly 1 lb a week.
What is the difference between BMR and TDEE?
BMR (basal metabolic rate) is the energy your body uses at complete rest just to stay alive. TDEE (total daily energy expenditure) adds everything else you do: walking, working, exercising and digesting food. TDEE is BMR multiplied by an activity factor from 1.2 to 1.9.
What is the Mifflin-St Jeor equation?
Published in 1990, it estimates BMR as 10 × weight (kg) + 6.25 × height (cm) − 5 × age, plus 5 for men or minus 161 for women. Studies have found it to be the most accurate of the common equations for most adults, which is why the Academy of Nutrition and Dietetics recommends it.
Is 1,200 calories a day enough?
1,200 calories is generally the lowest daily intake recommended for women, and 1,500 for men, unless a doctor supervises the diet. Below that it becomes hard to get enough protein, vitamins and minerals. This calculator never suggests a target below those limits.
How many calories are in a pound of fat?
A pound of body fat stores roughly 3,500 calories. That is the source of the 500-calories-a-day rule for losing 1 lb a week. Real weight loss slows over time because your maintenance calories fall as you get lighter, so recalculate every 10–15 lb.
Which activity level should I choose?
Choose sedentary if you have a desk job and do little planned exercise, lightly active for exercise 1–3 days a week, moderately active for 3–5 days, very active for hard exercise most days and extra active for a physical job plus training. If you are unsure, pick the lower level; most people overestimate their activity.
Why am I not losing weight on my calorie target?
The formula is an estimate and can be off by 10% or more for an individual. Food tracking is also easy to underestimate. Keep your intake consistent for 2–3 weeks, weigh yourself at the same time each day, and lower your target by 100–200 calories if the weekly average is not moving.
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