About this tool
This ideal weight calculator gives the body weight that four widely used clinical formulas consider ideal for your height and sex, side by side, so you can see how much they agree and where you fall. The Devine formula (1974) is the one most doctors and pharmacists still quote and is used to dose some medicines; Robinson (1983) and Miller (1983) were later refinements fitted to life-insurance mortality tables; Hamwi (1964) is the quick rule of thumb dietitians use. Each result is shown in kilograms and pounds, with the formula written out using your numbers, together with the average of the four and the healthy weight range implied by a BMI of 18.5 to 24.9. If you enter your current weight the page shows the difference from each figure. A reference table lists ideal weights across a range of heights for your sex. It is for adults who want a sensible target range, not a single magic number, and for students and clinicians checking a formula quickly.
How it works
All four formulas start from a base weight at 5 feet (152.4 cm) and add a fixed amount for every inch of height above that. Devine: men 50 kg + 2.3 kg per inch, women 45.5 kg + 2.3 kg per inch. Robinson: men 52 kg + 1.9 kg per inch, women 49 kg + 1.7 kg per inch. Miller: men 56.2 kg + 1.41 kg per inch, women 53.1 kg + 1.36 kg per inch. Hamwi: men 48 kg + 2.7 kg per inch, women 45.5 kg + 2.2 kg per inch. Height in centimeters is converted to inches by dividing by 2.54 and the fractional inches are kept, so a 180 cm man is 70.87 inches, 10.87 inches over five feet, and Devine gives 50 + 2.3 × 10.87 = 75.0 kg. For heights under five feet the formulas are extrapolated downward, which their authors never validated, and the page flags this. The BMI-based range multiplies height in meters squared by 18.5 and 24.9. Kilograms convert to pounds at 2.20462.
Frequently asked questions
Which ideal weight formula is the most accurate?
None of them was derived from health outcomes; they were fitted to insurance tables or simply proposed as convenient rules, so "accurate" is not quite the right word. Devine is the most widely used in medicine because drug dosing tables were built around it. Robinson and Miller give lighter figures for tall people and heavier ones for short people, while Hamwi swings the other way. Looking at the spread between them, and at the BMI range, is more informative than picking one.
Why do the formulas give different answers for the same height?
They were created in different decades from different data and with different purposes. Hamwi (1964) was a bedside rule for diabetic diet planning, Devine (1974) was proposed for calculating gentamicin doses, and Robinson and Miller (both 1983) were regression fits to Metropolitan Life Insurance mortality tables. The base weights and per-inch increments differ, so the results diverge more the further you are from about 5 ft 5 in, where they roughly agree.
Do these formulas work for very tall or short people, or for athletes?
They were validated only for adults roughly between 5 ft and 6 ft 4 in, and the per-inch increments become unrealistic outside that range; below 5 ft this page extrapolates and marks the result. None of the formulas consider frame size, muscle mass, age, or ethnicity, so muscular athletes will often exceed every ideal figure while being perfectly healthy. Waist circumference and body fat percentage are better guides in those cases.
What is a healthy weight, then?
For most adults a weight that puts BMI between 18.5 and 24.9 is considered healthy, which is a range of roughly 20 kg for an average-height person, much wider than the differences between the formulas. Within that range, a weight you can maintain with a normal diet and regular activity, with a waist under half your height, is a reasonable definition of healthy. Talk to a clinician before aiming for a weight below any of the figures shown here.