Ideal Body Weight Calculator

Devine is the default here and the most widely used in clinical settings — mainly because it's the formula most drug-dosing protocols were built around, not because it was ever validated as a health target. Robinson is a later refit of the same insurance height-weight tables and tends to sit a little lower than Devine. Miller runs flatter at the extremes and is sometimes preferred for very tall or very short people. If you're not sure, Devine is a reasonable default; the more useful number is the healthy weight range shown alongside it, and how much the four formulas agree or disagree at your height.

Because none of them measured you. Devine, Robinson, Hamwi and Miller were each fitted from a different source — a dosing note, insurance tables, a diabetes-care rule of thumb — decades apart, and Pai and Paloucek's 2000 review traced each one back to show none was derived from health outcomes. At an average height the four typically spread by 3-6 kg. That spread is the honest uncertainty in the whole concept of a single 'ideal' weight, not a bug in the calculator.

It applies a flat ±10% to whichever formula result you selected — small frame subtracts 10%, large frame adds 10%, medium frame leaves it unchanged. This comes from Hamwi's original rule of thumb, not from any measurement of your actual skeletal structure, so it reflects your own self-assessment of build rather than a bone-width measurement. Treat it as a rough adjustment, not a precise correction.

Not quite. Ideal body weight (IBW) is a height-and-sex based reference figure originally built for drug dosing calculations. The healthy weight range shown alongside it, based on a BMI of 18.5-24.9, is derived from population health outcomes and is generally the more clinically meaningful figure. IBW is useful as a rough reference point, especially in the clinical contexts it was designed for (dosing, ventilator settings), but it was never meant to be a personal target to hit.

Not well. All four formulas are linear equations based only on height and sex — they have no way to account for muscle mass. A muscular person can have a body weight well above their calculated IBW while carrying very little body fat, since none of these equations was built with athletes in mind. If build matters to your situation, a body fat percentage or a lean body mass calculation will tell you more than any of these four numbers.