### What is the definition of calorie?

*noun*

the energy needed to raise the temperature of 1 gram of water through 1 °C (now usually defined as 4.1868 joules).the energy needed to raise the temperature of 1 kilogram of water through 1 °C, equal to one thousand small calories and often used to measure the energy value of foods.

In nutrition, we deal with kilocalories (kcal), where 1 kcal is equal to a thousand of the "small" calories. As you could expect, 1 kcal = 4.18 kJ. (The web calculator on this page uses the term "calories" to describe kilocalories, like most healthy diet sources online).

### What does the calorie calculator do?

The calorie calculator, also called the Total Daily Energy Expenditure (TDEE) calculator, can help you determine how many calories should you eat per day, depending on whether you want to lose or maintain your weight.

### What is the equation used in the calorie calculator?

This Calorie Calculator is based on the Mifflin-St Jeor Equation, which is widely considered to be the most accurate equation for calculating the basal metabolic rate (BMR) for most people. The exception being that the Katch-McArdle Formula can be more accurate for leaner people who know their body fat percentage.

The Mifflin-St Jeor equation used by the calculator is:

For men: BMR = 10W + 6.25H - 5A + 5

For women: BMR = 10W + 6.25H - 5A - 161

where:

W is body weight in kg

H is body height in cm

A is age

F is body fat in percentage

Note: The calculator automatically converts pounds to kilograms and inches to centimeters.