Ideal weight calculator — four formulas compared
Compare what four classic formulas say your ideal weight should be — and see how much they disagree, which is the most honest answer this question has.
Runs entirely in your browser — nothing is uploaded.
These formulas come from 1960s–80s insurance tables built to estimate drug dosing, not health. They disagree with each other by several kilograms, which is the honest answer: there is no single ideal weight, only a healthy range.
How to use
- Enter your height. Metric or imperial.
- Select sex. Every one of these formulas uses different constants for men and women.
- Compare the results. The spread between formulas is itself the point — treat the healthy BMI range at the bottom as the more meaningful answer.
Questions
Why do the formulas disagree?
Because they were built for different purposes, decades apart, from different populations. Devine (1974) was created to calculate drug dosages, not to define health. Hamwi (1964) came from diabetes dietetics. None was derived from mortality or health-outcome data.
Is there really an ideal weight?
No single number, no. Health outcomes across a healthy BMI range are broadly similar, and body composition, fitness and fat distribution matter more than mass. That is why this tool shows a range alongside the formulas.
Why do these formulas use inches over five feet?
They were written in imperial units for American clinical use: take a base weight at 5 feet, then add a fixed amount per additional inch. It is why they behave oddly for very short adults — below 5 feet they start subtracting.
What should I use instead?
The healthy BMI range for your height as a rough boundary, plus waist-to-height ratio (aim below 0.5) as a better indicator of metabolic risk. For anything that matters, ask a clinician.