Our weight loss calorie calculator needs up to four of your measurements: height, neck, waist, and hips, to determine the percentage and mass of body fat which is integral in estimating the number of calories you need to forgo on a daily basis in order to achieve weight loss here is how to take the measurements, using a soft measurement tape:. How many calories need to lose weight. How many calories do you need to reduce by? so, how many calories can you eat and lose weight? studies have shown that women who eat 1000 fewer calories than they need lost around 2 pounds per week this is a healthy and sustainable level of weight loss the same rule applies to men. how many calories need to lose weight How many steps a day can help you lose weight ...