Calorie Calculator

Calculate daily calorie needs, weight loss calories, maintenance calories, and muscle gain nutrition targets.

Calorie Calculator

Estimate how many calories you need each day to maintain, lose, or gain weight. The calculator combines an estimate of your resting metabolism with an activity multiplier, then adjusts the total for your goal.

How daily calories are estimated

The calculation starts with basal metabolic rate (BMR), the energy your body uses at complete rest. This calculator uses the Mifflin-St Jeor equation, which is widely used in clinical nutrition:

  • Men: BMR = 10 x weight (kg) + 6.25 x height (cm) - 5 x age + 5
  • Women: BMR = 10 x weight (kg) + 6.25 x height (cm) - 5 x age - 161

BMR is then multiplied by an activity factor to estimate total daily energy expenditure (TDEE):

  • 1.2 for sedentary (little or no exercise);
  • 1.375 for light activity (exercise 1 to 3 days per week);
  • 1.55 for moderate activity (exercise 3 to 5 days per week);
  • 1.725 for very active (hard exercise 6 to 7 days per week); and
  • 1.9 for extremely active (physical job plus hard training).

TDEE is your estimated maintenance intake. A common planning approach subtracts roughly 500 kcal per day for gradual weight loss or adds 250 to 500 kcal per day for gradual weight gain.

Worked example

A 30-year-old woman who is 165 cm tall and weighs 60 kg has an estimated BMR of 10 x 60 + 6.25 x 165 - 5 x 30 - 161 = 1320 kcal (1320.25 before rounding). If she exercises three to five days a week, her maintenance estimate is 1320.25 x 1.55 = 2046 kcal per day. For gradual weight loss she might plan around 2046 - 500 = 1546 kcal per day.

How to interpret your result

The result is a planning estimate, not a measurement. Equations like Mifflin-St Jeor predict average energy needs for people of a given size, age, and sex, but individual metabolism can differ by several hundred calories because of genetics, body composition, hormones, medications, and daily movement outside formal exercise. Treat the number as a starting point, monitor your weight and energy levels over a few weeks, and adjust intake in small steps rather than assuming the estimate is exact.

Practical tips

  • Pick the activity level that matches a typical week, not your best week.
  • Track your weight trend for two to four weeks before changing your calorie target.
  • Avoid very large deficits; losing roughly 0.25 to 1 kg per week is a common gradual pace.
  • Recalculate after significant weight change, since BMR shifts as body weight shifts.
  • Pair a calorie target with adequate protein and mostly whole foods rather than focusing on calories alone.

Related calculators

Use the macro calculator to split a calorie target into protein, carbohydrate, and fat grams, and the TDEE calculator for a detailed look at daily energy expenditure. The body fat calculator estimates body composition, the meal calorie calculator helps total up individual meals, and the water intake calculator estimates daily fluid needs.

This calculator does not replace personalised advice from a qualified healthcare or nutrition professional.

Frequently asked questions

Which equation does the calorie calculator use?
It uses the Mifflin-St Jeor equation to estimate basal metabolic rate from your weight, height, age, and sex, then multiplies that by an activity factor between 1.2 and 1.9. Mifflin-St Jeor is widely recommended in clinical nutrition because it predicts resting energy needs well for most adults.
How many calories should I cut to lose weight?
A common planning approach is to eat about 500 kcal per day below your maintenance estimate, which corresponds to roughly 0.5 kg of loss per week on average. Smaller deficits are gentler and easier to sustain, while very large deficits are generally discouraged without professional supervision.
Why is my estimate different from my fitness tracker?
Formulas and trackers estimate energy needs in different ways, and both carry error of a few hundred calories. Formulas use population averages for your size and activity level, while trackers infer expenditure from movement and heart rate. Your own weight trend over several weeks is the most reliable reference.
Which activity level should I choose?
Pick the level that matches a typical week of deliberate exercise, not your most active week. Most people overestimate, so if you are between two levels the lower one is usually the safer starting point. You can adjust upward if you lose weight faster than expected at the resulting intake.
How often should I recalculate my calorie needs?
Recalculate after your weight changes by more than a few kilograms or when your activity routine changes meaningfully. Energy needs scale with body size, so a target set months ago can drift out of date as your weight moves.
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