How much weight you'll lose on a juice fast depends on your activity level and calorie intake. According to Harvard Health Publishing and other health organizations, it's necessary to ‌ burn about 3,500 calories to lose one pound of fat ‌. This number varies from one individual to another, though. This calculator will determine how many calories you should eat on a daily basis if you are trying to lose weight. Learn how many calories to lose weight safely, and how to lose weight fast. The weight losss calculator will only show you safe levels of calorie reduction. When selecting your activity level use: If you're planning to lose or gain weight, you will need to adjust the number obtained in the calculations described in the previous paragraph. It is typically assumed that each pound of body fat stores approximately 3500 kcal of energy. This is why you need a calorie deficit of 500 kcal a day to lose one pound or 0.5 kg a week. Naturally, if The BMI Formula. Body mass index (BMI) = weight (kg) ÷ height (m)2. BMI is a number generated by dividing your weight in kilograms by your height in metres squared. (You can convert from stones and pounds to kilos here .) The easiest way to work this out is to do the height multiplication first: height in meters x height in metres, then divide This free weight calculator converts between common units of weight and mass. Also, learn more about the origins of different units of weight. 1.15357 x 10 42 kg However, a simplified formula for estimating pant size changes due to weight loss is: Pant Size Change (PS) = (Weight Loss (WL) / Weight Loss Per Pant Size (WLS)) Pant Size Change (PS) represents the estimated change in pant size. Weight Loss (WL) is the amount of weight lost, typically measured in pounds (lb) or kilograms (kg). On average gastric bypass patients lose about 70% (Bariatric Surgery, A Systemic Review and Meta Analysis, 2004) of their excess weight. To simplify, 70% is a good number to use when figuring your expected weight loss after gastric bypass. How To Calculate Your Expected Weight Loss After Gastric Bypass For Women: BMR = (10 × weight in kg) + (6.25 × height in cm) – (5 × age in years) – 161. Since most people measure their weight in pounds, you first need to convert this to kilograms by dividing your weight by 2.2. If you are using inches for height, multiply this by 2.54 to determine your height in centimeters. XAyJV.