Excess Body Weight Calculator

How it is calculated

The tool takes two weights you supply and compares them: excess = current − ideal and excess % = (current − ideal) ÷ ideal × 100. The base of the percentage is the ideal weight, not the current weight. The ideal weight is not calculated for you; you bring it from a formula or a target set with your care team, and the tool simply echoes it back. Both values must be in the same unit; choose kilograms or pounds with the units setting (anything other than kg is read as pounds). Both weights must be positive and, once converted, between 2 kg and 650 kg; a value outside that range shows no result. If you weigh less than the ideal figure, the results are negative, meaning you are below it. The tool does not judge whether the ideal you typed is realistic or healthy for your height.

Common mistakes

• Entering a body-mass-index target or a height-based number in the ideal-weight field instead of a weight. A BMI of 22 typed as a weight is accepted as 22 kg and gives a meaningless result, so the tool cannot catch it.
• Mixing kilograms and pounds between the two fields; the tool subtracts them as they are, under the one unit you selected.
• Dividing the excess by the current weight in your head and getting a smaller percentage than the tool, which divides by the ideal weight.
• Leaving the units on pounds while typing kilograms: 70 is then read as 70 lb (about 32 kg), and the result is wrong without any warning.
• Treating the figure as a diagnosis or as a loss target in itself: it depends entirely on which ideal weight you chose, and different formulas give ideals several kilograms apart.