Where ideal weight formulas come from
Ideal body weight formulas were created mainly for medical use, especially for calculating drug doses, rather than to tell people what they should weigh. The best known is the Devine formula from 1974: 50 kg plus 2.3 kg for every inch over 5 feet for men, and 45.5 kg plus 2.3 kg per inch for women. Later researchers proposed adjustments based on insurance and population data. Robinson (1983) uses 52 kg + 1.9 kg per inch for men and 49 kg + 1.7 kg per inch for women. Miller (1983) uses 56.2 kg + 1.41 kg and 53.1 kg + 1.36 kg. Hamwi (1964) uses 48 kg + 2.7 kg and 45.5 kg + 2.2 kg.
For a man who is 5 ft 10 in (70 inches) the formulas give 73.0 kg (Devine), 71.0 kg (Robinson), 70.3 kg (Miller) and 75.0 kg (Hamwi), a spread of about 10 lb.
Why we show the BMI range first
Each formula produces a single number, which can make it look more precise than it is. Healthy people of the same height can differ by 10 to 15 kg because of frame size, muscle and bone density. For that reason the main result is the weight range that corresponds to a BMI of 18.5 to 24.9 for your height, which is the range most health agencies use. The four formulas are listed below so you can see where they fall within, or sometimes slightly outside, that range.
Frame size and body composition
A simple way to judge frame size is wrist circumference. For women of average height, a wrist under about 6 inches suggests a small frame and over 6.25 inches a large frame; for men, the cut-offs are around 6.5 and 7.5 inches. People with a larger frame or more muscle can be perfectly healthy toward the top of the range, while those with a smaller frame may feel best toward the bottom. Body fat percentage, waist size and fitness tell you more about health than weight alone.
Limits of these formulas
The formulas assume heights over 5 feet, and they become unreliable for people who are very short or very tall, so this calculator only accepts heights between 140 and 230 cm. They do not account for age, ethnicity or athletic build, and they were never intended for children or pregnant women. Use the results as a rough guide when setting a goal, then focus on behaviors such as regular activity, good sleep and a balanced diet. If you are trying to lose or gain a large amount of weight, a doctor or dietitian can help you choose a realistic target.
Frequently asked questions
What is my ideal weight for my height?
A practical answer is the healthy BMI range for your height, shown as the main result. The formulas give single points that usually fall inside that range.
Which ideal weight formula is best?
None is clearly best for everyone. Devine is most common in medicine, while Robinson and Miller are newer refinements. Looking at all of them gives a sensible range.
Do these formulas work for short people?
They are designed for people over 5 feet tall. Below that they can give unrealistically low values.
Does muscle affect ideal weight?
Yes. Muscular people can weigh more than these formulas suggest while having low body fat and good health.