Key takeaways
- 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.
What this tool does
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. The tool shows several next to a BMI range 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. [insert each formula's coefficients from a cited source]
BMI range: weight = BMI × height (m)². For a height, multiply the lower and upper BMI limits by that squared. [verify BMI range from a named health body]
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.
What to check against your label
- That formulas ignore muscle, bone and age.
- What your clinician considers a reasonable goal.
Frequently asked questions
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.
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.
- Formula sources. [original papers or reviews]