BMR calculator: basal metabolic rate and daily calorie needs

The calculator estimates how much energy your body uses at rest and on a normal day. It uses the Henry equations, which the European Food Safety Authority (EFSA) uses for its reference values for energy.

What is basal metabolic rate?

Your basal metabolic rate (BMR) is the energy your body needs to stay alive at complete rest: to keep the heart beating, the brain working, the lungs breathing and the body warm. For most adults it is more than half of what they burn in a day.

Your total daily need is your BMR multiplied by your physical activity level (PAL). A PAL of 1.4 means a sedentary life, and 1.6 means a desk job with some walking and exercise. EFSA uses PAL values from 1.4 to 2.0 for its reference values.

How many calories do you need?

Here are the daily calorie needs for two example people at three activity levels, calculated with the same Henry equations as the calculator. Taller, heavier or more active people need more; shorter, lighter or less active people need less.

	Sedentary (PAL 1.4)	Moderately active (1.6)	Active (1.8)
Woman, 25 (165 cm, 62 kg)	1,920 kcal	2,200 kcal	2,470 kcal
Woman, 45 (165 cm, 62 kg)	1,850 kcal	2,120 kcal	2,380 kcal
Woman, 65 (165 cm, 62 kg)	1,730 kcal	1,970 kcal	2,220 kcal
Man, 25 (178 cm, 78 kg)	2,500 kcal	2,860 kcal	3,220 kcal
Man, 45 (178 cm, 78 kg)	2,400 kcal	2,740 kcal	3,080 kcal
Man, 65 (178 cm, 78 kg)	2,240 kcal	2,550 kcal	2,870 kcal

How the calculator works

First, the calculator works out your BMR with the Henry equations, which use sex, age, weight and height. They were developed at Oxford Brookes University from a large international dataset, and EFSA chose them for the European reference values (Henry, 2005; EFSA, 2013). One megajoule (MJ) is about 239 kilocalories (kcal).

For comparison, the calculator also shows the Mifflin–St Jeor equation, which many US calculators use. It was developed from measurements in 498 healthy adults, and in the same study the old Harris–Benedict equations from 1919 overestimated BMR by about 5 % (Mifflin et al., 1990).

Calories and weight loss

To lose weight, you need to take in less energy than you use over time. How fast it goes varies a lot from person to person, and the calculator only gives a starting point. Our weight loss page covers the habits with the best evidence, from sleep to protein.

Calories are only part of the picture. Your waist-to-height ratio often says more about health risk than your weight alone.

Frequently asked questions

What is the difference between BMR and daily calorie needs?

Your basal metabolic rate (BMR) is the energy your body uses at complete rest, for the heart, brain, breathing and temperature. Your daily calorie needs are your BMR multiplied by your activity level, so they include everything you do in a day.

How many calories should I eat a day?

It depends on your sex, age, size and how active you are. With the Henry equations, a 45-year-old woman of 165 cm and 62 kg with a moderately active life needs about 2,120 kcal a day. A man of 178 cm and 78 kg at the same age needs about 2,740 kcal.

Which BMR formula is the most accurate?

The European Food Safety Authority (EFSA) uses the Henry equations, which are based on a large international dataset. The Mifflin–St Jeor equation is widely used in the US and gives similar results. Both are averages, and your own BMR can be higher or lower.

How accurate is a calorie calculator?

It gives an estimate based on averages from large studies, and individuals can be a fair bit above or below. The best test is your weight over time: if it stays stable for a few weeks, you are eating about what you use.

Sources

• EFSA (2013): Scientific Opinion on Dietary Reference Values for energy, EFSA Journal
• Henry (2005): Basal metabolic rate studies in humans: measurement and development of new equations, Public Health Nutr
• Mifflin et al. (1990): A new predictive equation for resting energy expenditure in healthy individuals, Am J Clin Nutr

The calculator gives an estimate based on formulas and averages from large studies. It does not replace an assessment by a doctor. The numbers you enter stay in your browser and are not stored.