Ideal Weight Calculator

How to use the ideal weight calculator

1. Fill in the fields — they start with a worked example.
2. Read the answer, and the arithmetic shown beneath it.
3. Copy the results, or adjust the inputs to compare scenarios.

About this tool

There is no single ideal weight, and this tool shows several answers rather than pretending otherwise. The BMI range (18.5–24.9) gives a band; the Devine, Robinson and Hamwi formulas each give a single number, and they disagree with each other by several kilograms.

That disagreement is the useful part. The clinical formulas were built for drug dosing in the 1970s, not for health targets, and none of them accounts for build, muscle or where weight is carried. A range is a more honest answer than a number.

Common uses

• Seeing the healthy weight band for a given height.
• Understanding why different sources quote different targets.
• Setting a realistic range rather than a single figure.

Frequently asked questions

Why do the formulas disagree?

They were derived from different populations for different purposes — mostly medication dosing rather than health. Treat the spread as the honest answer.

Which should I use?

The BMI range is the most widely used for health. Even that is a screening tool, not a diagnosis.