The rules of gaining or losing weight are simple: if you eat more calories than you burn you’ll gain weight; if you eat less than you burn then you’ll lose weight. Forget the gimmicks, fancy diets and pills - it’s as simple as that.

Input your gender, weight, height, age and typical weekly activity level below and the calculator will work how many calories you typically burn in a day. This is often known as your Total Daily Energy Expenditure or TDEE. It does this by taking into account your gender, weight, height, age and typical activity level.

If you consume this number of calories you will maintain your current weight.

The calculator will also provide you with your body mass index (BMI) using your weight and height. Please note that if you are at the extremes in terms of very little body fat or excessive body fat then the BMI may not provide you with a truly accurate figure.

If you sign up as a registered user you will be able set yourself a weight target and a timescale. This might be an increase in weight (eg. Bodybuilding) or a decrease in weight.  The calculator will then work out how many calories you need to lose or gain per day in order to achieve your target.

Please note: the calculator is based on the average person. If you are extremely muscular the calculator may underestimate TDEE or if you are extremely overfat the calculator may overestimate TDEE

In addition to the calorie counter you may also be interested in your Waist-to-Hip ratio. The ratio of waist size to hip size is used to indicate whether, for the average person, you are considered healthy or at risk of heart attack.  Click here for more!

Before we start, we need to know how you like to measure your height and weight: