How ideal weight calculator works
Ideal body weight (IBW) is an estimate of the weight associated with the lowest health risk for a given height. Several formulas were developed from insurance and population data in the 20th century. None is perfect, but together they give a useful target range rather than a single number.
This calculator reports four classic formulas. Each starts with a base weight at 5 feet tall (152 cm) and adds a fixed number of kilograms for every inch over 5 feet, with different bases and increments for men and women. Devine (the most cited) uses 50 kg plus 2.3 kg per inch for men; Robinson, Hamwi, and Miller use slightly different constants.
Enter your gender and height in centimetres. The calculator converts to inches, applies each formula, and lists all four results so you can see the spread. Treat the range as a rough guide — healthy weight depends on muscle mass, frame size, and body composition, not height and gender alone. Consult a healthcare professional for personal advice.
Frequently asked questions
Which ideal weight formula is most accurate?
The Devine formula is the most widely cited and used by many drug-dosing references. Because the four formulas give slightly different numbers, this calculator shows all of them so you can use the range rather than a single value.
Why are there four different results?
Each formula was derived from a different population and study — Devine (1974), Robinson (1983), Hamwi (1964), and Miller (1983). They use different base weights and per-inch increments, so they disagree by a few kilograms. The spread is a useful reminder that "ideal" is a range, not a point.
What height does the formula use?
All four formulas add weight for every inch above 5 feet (60 inches). If you are shorter than 5 feet, the calculator clamps the "inches over 5 feet" at zero and uses just the base weight, matching the standard convention.
Does ideal weight account for muscle or frame size?
No. These formulas use only height and gender, so they ignore muscle mass, bone density, and body composition. A muscular person may be healthy well above the estimate. Use the result as a rough reference, not a target you must hit.
