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BMR & calorie calculator

Find your BMR (the calories your body burns at rest) and, from your activity level, the daily calories to maintain, lose or gain weight. Uses the Mifflin–St Jeor formula doctors and dietitians trust.

1You

How active you are on a typical day, for the daily-calorie figures.

Your results

Your results appear here

Type your measurements in the empty boxes. Still needed:

  • Age (years)
  • Weight
  • Height
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  • Any unit
  • PDF & CSV

How to calculate your calorie needs

  1. 1Choose your sex and enter your age.
  2. 2Enter your weight and height.
  3. 3Pick your activity level.
  4. 4Read your BMR and the daily calories to maintain, lose or gain weight.

BMR & calorie formula (Mifflin–St Jeor)

  1. 01Mifflin–St Jeor BMR = 10 × kg + 6.25 × cm − 5 × age + s
  2. 02s = +5 for men, −161 for women
  3. 03Maintenance calories = BMR × activity factor (1.2 to 1.9)
  4. 04Lose ≈ maintenance − 500 · Gain ≈ maintenance + 500

Your basal metabolic rate (BMR) is the energy your body uses just to keep running at rest — breathing, circulation, keeping warm. The Mifflin–St Jeor equation estimates it from your weight, height, age and sex, and is one of the most accurate simple formulas.

Few people rest all day, so your maintenance calories — your total daily energy expenditure — are your BMR times an activity factor, from 1.2 for a desk-bound day to 1.9 for hard daily training. Eating that many calories keeps your weight steady.

To lose about half a kilo a week, eat roughly 500 calories below maintenance; to gain, eat about 500 above, ideally with strength training. These are estimates — real needs vary, so adjust by watching your weight over a few weeks.

Calorie calculation example

At 30 years and 70 kg, your BMR is about 1,649 calories a day.

With your activity level, about 2,556 calories maintain your weight.

Good to know

  • These are estimates — adjust by tracking your weight over 2–3 weeks and tweaking calories up or down.
  • Protein and strength training help you keep muscle when losing weight.
  • Very large daily deficits backfire; a 500-calorie deficit is sustainable for most people.

Calorie calculator — common questions

What is BMR?

Basal metabolic rate — the calories your body burns at complete rest to stay alive. It's the base of your daily calorie needs.

How many calories should I eat to lose weight?

Roughly 500 calories below your maintenance level loses about half a kilo a week. This calculator shows that figure for your details and activity.

What is the Mifflin–St Jeor formula?

A well-regarded BMR equation: 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5 for men (−161 for women).

Why do people with the same weight need different calories?

Age, height, sex and especially activity level change the total. A taller, younger or more active person burns more.

Sources

Formulas last reviewed: September 30, 2026 ·How we check our formulas

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