Ideal weight estimate
Free calculator, no sign-up
A rough target weight from height, using a common clinical formula.
Enter your numbers
Arithmetic on the numbers you enter. Check the result against your pharmacy label and ask your prescriber. Reko does not suggest doses, and this is not medical advice.
How it works
The Devine formula: 50 kg (men) or 45.5 kg (women) plus 2.3 kg per inch over 5 feet.
Check it against your label
- That formulas ignore muscle, bone and age.
- What your clinician considers a reasonable goal.
| Formula | Men | Women |
|---|---|---|
| Hamwi, 1964 | 106 lb + 6 lb per inch | 100 lb + 5 lb per inch |
| Devine, 1974 | 50 kg + 2.3 kg per inch | 45.5 kg + 2.3 kg per inch |
| Robinson, 1983 | 52 kg + 1.9 kg per inch | 49 kg + 1.7 kg per inch |
| Miller, 1983 | 56.2 kg + 1.41 kg per inch | 53.1 kg + 1.36 kg per inch |
Inches are counted above 5 feet. Our calculator uses Devine.
Frequently asked questions
In short
- Each formula adds a number of kilograms for each inch over five feet.
- The four results disagree, which tells you something.
- BMI = weight (kg) ÷ height (m)².
- A goal weight is for you and your clinician to set.
Which formula is right?
None of them is right for everyone.
Should I aim for the result?
That is for you and your clinician.
Why is BMI shown?
It is a common screening range, with known limits.
What does this tool do?
These formulas take height and sex and return a weight. They were written for other purposes, such as dose scaling, and ignore build and muscle. This calculator shows the Devine result. The table below gives the others, so you can see how far apart they are.
How the arithmetic works
Hamwi, Devine, Robinson and Miller each have a base value and a per-inch increment, differing by sex. The table below gives each one.
BMI range: weight = BMI × height (m)². For a height, multiply the lower and upper BMI limits by that squared. The World Health Organization puts normal weight at a BMI of 18.5 to 24.9.
A worked example
Example. These numbers are made up to show the steps. They are not a label value and not a suggestion.
Made-up: a height of 1.70 m. If a BMI range of 20 to 25 were used: 20 × 2.89 = 57.8 kg, 25 × 2.89 = 72.25 kg.
- Peterson CM, et al. Universal equation for estimating ideal body weight. Am J Clin Nutr. 2016;103(5):1197-1203.
- Pai MP, Paloucek FP. The origin of the "ideal" body weight equations. Ann Pharmacother. 2000;34(9):1066-9.
- World Health Organization Europe, Nutrition for a healthy life.
Related pages
How Reko does this in the app
Reko does not set a goal weight for you. It records weight over time in lb, st or kg so you can look at the line your own record draws.
Reko records what you and your prescriber decide. It never suggests a dose, and this page is not medical advice.