Calorie Calculator

Find out how many calories you need each day with this free daily calorie calculator. It uses the Mifflin-St Jeor equation to estimate your basal metabolic rate (BMR), then multiplies it by your activity level to give daily calories for maintaining, losing, or gaining weight. Pick US or metric units, enter your age, sex, weight, height, and activity, and see your numbers instantly. Everything runs in your browser, so your details never leave your device.

Estimate only — not medical advice. Talk to a healthcare professional about personal decisions.

How the Mifflin-St Jeor equation works

The Mifflin-St Jeor equation estimates how many calories your body burns at complete rest. This is called your basal metabolic rate, or BMR. It uses your weight, height, age, and sex.

For men: BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age (years) + 5
For women: BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age (years) − 161

Your daily calories are your BMR multiplied by an activity factor:

  • Sedentary (little or no exercise): × 1.2
  • Lightly active (light exercise 1–3 days a week): × 1.375
  • Moderately active (moderate exercise 3–5 days a week): × 1.55
  • Very active (hard exercise 6–7 days a week): × 1.725
  • Extra active (very hard exercise or a physical job): × 1.9

The lose target subtracts about 500 kcal from the maintain figure. The gain target adds about 500 kcal.

Solved example: man, 30, 70 kg, 175 cm

A 30-year-old man weighs 70 kg and is 175 cm tall. He exercises moderately 3–5 days a week.

  1. BMR = 10 × 70 + 6.25 × 175 − 5 × 30 + 5 = 700 + 1,093.75 − 150 + 5 = 1,648.75 kcal/day.
  2. The activity factor for moderately active is 1.55.
  3. 1,648.75 × 1.55 = 2,555.56 kcal/day to maintain weight.
  4. Lose target = 2,555.56 − 500 = 2,055.56 kcal/day. Gain target = 2,555.56 + 500 = 3,055.56 kcal/day.

How to use this calculator

  1. Choose US or metric units, then select your sex and type your age, weight, and height.
  2. Pick the activity level that best matches your normal week.
  3. Press Calculate and read your BMR and your daily calorie targets for maintaining, losing, or gaining weight.

What the activity levels mean

Be honest about your normal week. Most people overestimate how active they are.

  • Sedentary means you sit most of the day and do little or no planned exercise.
  • Lightly active means light exercise such as easy walks 1–3 days a week.
  • Moderately active means exercise that raises your heart rate, such as brisk walking, cycling, or swimming, 3–5 days a week.
  • Very active means hard workouts 6–7 days a week.
  • Extra active means very hard training twice a day or a heavy physical job plus training.

If you are between two levels, start with the lower one. You can adjust after a few weeks of watching your weight.

Limits: calorie estimates are not medical advice

This calculator gives an estimate only. It is not medical advice, and it does not diagnose any condition or recommend a personal diet. The equation cannot account for muscle mass, hormones, illness, medication, or how your body adapts over time, so your true needs may be several hundred calories higher or lower.

Do not use the lose or gain targets to set an extreme diet. Talk to a healthcare professional or a registered dietitian before making big changes to what you eat, especially if you are pregnant, breastfeeding, managing a health condition, or under 18.

All calculations run in your browser. Nothing you type is sent, stored, or logged anywhere.

Frequently asked questions

What is BMR in this daily calorie calculator?

BMR stands for basal metabolic rate. It is the number of calories your body would burn in a day at complete rest, just to keep you alive. This calculator works out your BMR first, then adds your activity on top.

Why does the calculator ask for my sex?

Men and women of the same weight, height, and age tend to burn slightly different amounts at rest, because body composition differs on average. The Mifflin-St Jeor equation has a small adjustment for this, which is why the calculator asks.

How fast will I lose weight on the lose target?

The lose target is about 500 kcal below your maintain level. In theory that leads to roughly half a kilogram (about a pound) of weight loss per week. In practice it varies a lot from person to person, and weight loss usually slows over time.

Should I eat back the calories I burn exercising?

The activity factor already includes your exercise, so the maintain figure covers a typical training week. Eating back extra calories on top often cancels out the exercise. If you add a big new workout, give it a few weeks and watch the scale before changing your intake.

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