Your calorie needs
Find out the energy you burn daily.
If you enter your body fat, the calculation switches to the Katch-McArdle method for higher accuracy. Leave it blank if you don't know it.
What Are Calorie Needs?
Your calorie needs are the amount of energy your body requires to function properly throughout the day — spent on everything from breathing and your heartbeat to moving and thinking. In short, calories are your body's fuel.
This need has three components: the largest is your basal metabolism, the energy spent even at rest (about two-thirds of daily expenditure); the second is the energy spent on movement during the day; the third is the small share used to digest food.
Age, gender, height, weight, muscle mass and activity level determine this value. Knowing your calorie needs is a healthy starting point for losing, maintaining or gaining weight. Eat less than you need and you lose weight; eat more and you gain.
How Are Calorie Needs Calculated?
Calorie needs are calculated in two stages: first the resting expenditure (BMR), then the daily total (TDEE) by multiplying that value by your activity level.
1. Basal metabolic rate (BMR). The energy spent on vital functions while completely at rest; the Mifflin-St Jeor equation is commonly used.
If your body fat is known, the calculation switches to the Katch-McArdle method, which is based on lean mass instead of total weight and gives a more personal result.
2. Total daily energy (TDEE). The base value is multiplied by your activity level to reach total daily expenditure: TDEE = BMR × activity factor.
Choosing your activity level as realistically as possible is critical for accuracy. The resulting TDEE is the calories needed to maintain your weight; create a deficit to lose weight (usually 300–500 kcal per day) or a surplus to gain.