Decision tools built for clarity
Ideal Weight Formula Comparison
Compare four historical height-based ideal-body-weight formulas and their spread.
Enter the required values, select the applicable options, and calculate.
“Ideal weight” is a historical term; these formulas do not define a healthy target for an individual.
Methodology
Formula or transformation
Compares the Devine, Robinson, Miller, and Hamwi historical height-based equations, each evaluated on its own from the height in inches over 5 feet. Devine: 50 kg + 2.3 kg per inch over 5 feet (men), 45.5 kg + 2.3 kg (women). Robinson: 51.65 kg + 1.85 kg per inch over 5 feet (men), 48.67 kg + 1.65 kg (women), the coefficients published in the 1983 paper rather than the commonly rounded 52/1.9 and 49/1.7. Miller: 56.2 kg + 1.41 kg (men), 53.1 kg + 1.36 kg (women). Hamwi: 106 lb + 6 lb (men), 100 lb + 5 lb (women), converted at exactly 0.45359237 kg per pound.
Variables
- Height in inches above five feet
- Devine estimate in kilograms
- Robinson estimate in kilograms
- Miller estimate in kilograms
- Hamwi estimate in kilograms
Units
- Inch
- Kilogram
- Pound
Rounding policy
Kilogram estimates are rounded to the declared result scale using half away from zero.
Devine, Robinson, Miller, and Hamwi estimates are calculated independently from sex and height, then summarized as a range.
Compare four historical height-based ideal-body-weight formulas and their spread.
Reviewed sources
- PubMed / U.S. National Library of Medicine — The origin of the ideal body weight equations Reviewed on 2026-09-07
- PubMed / U.S. National Library of Medicine — Robinson ideal body weight formula record Reviewed on 2026-09-07
- PubMed / U.S. National Library of Medicine — Determining ideal body weight and mass Reviewed on 2026-09-07
- PubMed Central — Historical cautions about ideal body weight Reviewed on 2026-09-07
Formula review history
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Initial historical formula and source review.
Reviewed 2026-09-07 for formula version historical-reference-weight-comparison-v1
Assumptions
- Inputs are interpreted using the displayed units and options.
- The calculation follows the methodology and factors listed in the sources.
Limitations
- Display rounding can hide additional decimal places.
- The calculation cannot add accuracy that is absent from the submitted inputs.
- “Ideal weight” is a historical term; these formulas do not define a healthy target for an individual.
Worked example
For a 70-inch male, the four estimates range from 70.15 kg to about 75.30 kg.
Frequently asked questions
Why are there four different numbers?
Each historical equation was fitted for a different purpose, such as drug dosing or insurance tables, so they disagree by a few kilograms. The calculator shows all four and their spread instead of averaging them into one target.
Why is a height under five feet refused?
The equations are anchored at five feet and add a fixed amount per inch above it; below that height they were never published, so the calculator does not extrapolate.