Complete guide
Ideal weight calculator: compare formulas and a BMI reference range
Enter adult height and equation sex to compare four historical reference-weight formulas. Calculator24 also shows the weight interval corresponding to the CDC adult healthy-BMI category, so one formula is never presented as a universal target.
What ideal weight formulas estimate
Devine, Robinson, Miller and Hamwi are height- and sex-based reference equations. They cannot see muscle, fat distribution, age, medical history, pregnancy, disability or athletic training.
Four historical equations
Each equation starts with a base weight at five feet and adds kilograms or pounds for each inch above five feet. They produce different answers because their coefficients and original purposes differ.
Devine: male 50+2.3i; female 45.5+2.3i kgRobinson: male 52+1.9i; female 49+1.7i kgMiller: male 56.2+1.41i; female 53.1+1.36i kgHamwi: male 106+6i; female 100+5i lbBMI-based reference interval
For adults, CDC labels BMI from 18.5 to below 25 as healthy weight. Multiplying the boundary BMI values by height squared converts that category into a height-specific weight interval.
lower weight=18.5×height²upper weight=24.9×height²Worked example
At 165 cm, height is about 64.96 inches, or 4.96 inches above five feet. Applying the four female coefficients produces different reference values; the calculator reports their average and every individual estimate.
Why the formulas disagree
The formulas arose in different eras and clinical contexts. A review of their history found that the popular Devine equation was originally proposed for drug dosing rather than as a population health target.
How to interpret the result
Treat the display as a comparison of simple references. CDC describes BMI as a screening measure, so weight decisions should also consider clinical history, body composition, sustainable behavior and professional advice when appropriate.
Equation bases at five feet
| Formula | Male base | Female base |
|---|---|---|
| Devine | 50 kg | 45.5 kg |
| Robinson | 52 kg | 49 kg |
| Miller | 56.2 kg | 53.1 kg |
| Hamwi | 106 lb | 100 lb |
Frequently asked questions
Is there one scientifically correct ideal weight?
No. The equations give different height-based references and omit many individual factors.
What height range is supported?
This implementation supports adult heights from five to eight feet, with equivalent metric inputs.
Why include BMI?
It provides a familiar adult screening interval rather than one point estimate.
Was the Devine formula designed for weight loss?
No. Historical research traces it to drug-dosing guidance.
Do these formulas measure body fat?
No. They use only height and equation sex.
Should I aim for the displayed average?
The average is a comparison statistic, not a medical prescription.
What to keep in mind
There is no single ideal weight. These historical formulas were created for clinical dosing or reference uses and do not measure health or body composition. BMI is also a screening measure.
Results display up to 8 decimal places; exported numbers preserve calculation precision. This is a calculation summary, not an official certificate.