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Calorie Calculator

Your daily calorie need (TDEE) is your basal metabolic rate multiplied by an activity factor. Using the Mifflin-St Jeor equation, a 34-year-old woman who is 168 cm, 64 kg and moderately active burns about 2,106 calories a day. Eating about 500 fewer loses roughly 0.5 kg a week.

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Sex
yrs
Maintenance calories2,106 kcalper day
Maintenance (TDEE)2,106 kcal
Basal metabolic rate1,359 kcal
Protein 30% of calories158 g
Carbohydrates 40% of calories211 g
Fat 30% of calories70 g

Mifflin-St Jeor BMR × activity factor. 1 kg of body weight is about 7,700 kcal, so 500 kcal a day is about 0.5 kg a week.

How to use the Calorie Calculator

  1. Choose female or male and enter your age.
  2. Enter your weight (kg or lb) and height (cm or inches).
  3. Pick the activity level that matches a typical week.
  4. Read your maintenance calories, a target for losing about 0.5 kg a week, and your BMR.

Formula

BMR = 10 × weight (kg) + 6.25 × height (cm) - 5 × age + 5 (men) or - 161 (women) · TDEE = BMR × activity factor

The Mifflin-St Jeor equation estimates basal metabolic rate. Activity factors are 1.2 (desk job), 1.375 (1 to 3 workouts a week), 1.55 (3 to 5), 1.725 (6 to 7) and 1.9 (athlete or physical job). The weight-loss target subtracts 500 kcal a day.

Safe rates of change

  • Losing about 0.5 to 1 kg (1 to 2 lb) a week is considered safe and sustainable for most adults.
  • That needs a daily deficit of roughly 500 to 1,000 calories.
  • Women generally should not go below about 1,200 calories a day, and men below about 1,500, without medical supervision.

What changes your metabolism

  • Age: needs fall gradually from early adulthood, mainly as muscle declines.
  • Muscle mass: more muscle raises resting energy use.
  • Body size: heavier and taller people burn more.
  • Genetics, hormones, sleep quality and stress.

Calorie Calculator questions

How many calories should I eat per day to lose weight?

Eat about 300 to 500 calories below your maintenance (TDEE) figure. That deficit typically produces a loss of 0.25 to 0.5 kg a week. Avoid going below about 1,200 calories a day for women or 1,500 for men without medical advice, as very low intakes are hard to sustain.

What is the difference between BMR and TDEE?

BMR (basal metabolic rate) is the energy your body uses at complete rest for breathing, circulation and organ function. TDEE (total daily energy expenditure) adds everything you do on top, from walking to workouts. TDEE is the number to use for eating targets.

How accurate are calorie calculators?

They are estimates, usually within about 10% for most people. The Mifflin-St Jeor equation is considered one of the most accurate for healthy adults. Use the result as a starting point, track your weight for two to three weeks, then adjust by 100 to 200 calories if needed.

How do I choose the right activity level?

Pick the level that describes an average week, not your best one. Desk job with little exercise is 1.2, one to three workouts is 1.375, three to five is 1.55, six to seven is 1.725, and a physical job or athlete training is 1.9. Most people overestimate activity, so round down if unsure.

What happens if I eat too few calories?

Very low intakes can cause muscle loss, fatigue, nutrient deficiencies and rebound overeating, and your body adapts by burning slightly less. A moderate deficit preserves muscle and is easier to maintain, especially when combined with strength training and enough protein.

How do I adjust calories as I lose weight?

Recalculate after every 5 kg (about 10 lb) lost, or whenever weight loss stalls for more than two weeks. A lighter body needs fewer calories, so the same intake gradually becomes maintenance. Update your weight in the calculator and set a new target.

Do men and women have different calorie needs?

Yes. At the same age, height and weight, the Mifflin-St Jeor equation gives men 166 more calories a day at rest, mainly because men carry more lean mass on average. Body size and activity still matter far more than sex alone.

How does age affect calorie needs?

Each additional year of age lowers the estimated BMR by 5 calories in the Mifflin-St Jeor equation, so a 50-year-old needs about 100 fewer calories at rest than an otherwise identical 30-year-old. Strength training helps keep muscle and slows the decline.

Can I use this calculator if I have a medical condition?

It is designed for healthy adults. If you have diabetes, a thyroid disorder or another metabolic condition, are pregnant or breastfeeding, or take medication that affects weight, ask your doctor or a registered dietitian for a personalized target.