Calculator
Ideal Weight Calculator
Compare Devine, Robinson, Miller, and Hamwi ideal-weight estimates. See the formulas side by side and understand why they produce different answers.
Compare four ideal-weight formulas
Formula estimates
Why there is no single ideal-weight formula
"Ideal weight" is a historical term used by several height-weight equations. Different formulas were developed from different datasets and assumptions, so they can produce meaningfully different estimates for the same height. This calculator makes that disagreement visible instead of hiding it behind one number.
Formula comparison
| Formula | Men | Women |
|---|---|---|
| Devine | 50 + 2.3 × inches over 60 | 45.5 + 2.3 × inches over 60 |
| Robinson | 52 + 1.9 × inches over 60 | 49 + 1.7 × inches over 60 |
| Miller | 56.2 + 1.41 × inches over 60 | 53.1 + 1.36 × inches over 60 |
| Hamwi | 106 lb + 6 lb × inches over 60 | 100 lb + 5 lb × inches over 60 |
The equations above are shown in their commonly cited forms. The calculator converts the Hamwi result to kilograms so the results can be compared on one scale.
Worked example
For a hypothetical 175 cm adult, height is about 68.9 inches, or 8.9 inches over 5 feet. Because each formula applies a different slope and starting value, the four results will not match. The calculator also shows their simple average as a reference, but that average is not itself a validated medical target.
How to use the estimates
Use these formulas to understand how historical height-weight estimates differ, not to decide that one number is your "correct" weight. In clinical settings, some ideal-weight equations have specific applications, such as medication dosing, and the appropriate formula can depend on the task. A general consumer calculator should not turn these estimates into medication instructions.
Limitations
- Different formulas produce different estimates.
- Many formulas were developed for specific historical purposes.
- They do not directly measure body fat or body composition.
- They are not individualized medical advice.
- For people outside the populations or height ranges underlying a formula, interpretation can be less useful.
Frequently asked questions
What is ideal weight?
It is a historical mathematical estimate derived from height-weight relationships; it is not one universally correct body weight.
Why do formulas disagree?
They were developed from different assumptions and source data and use different slopes and reference values.
Which formula is best?
There is no universal winner for all purposes. The appropriate method depends on the context.
What is the Devine formula?
It estimates 50 kg plus 2.3 kg per inch over 5 feet for men and 45.5 kg plus 2.3 kg per inch for women.
Does ideal weight equal healthy weight?
No. Ideal-weight formulas and BMI-based healthy-weight ranges answer different mathematical questions.
Can I use these formulas for children?
No. Pediatric weight assessment uses growth references and age-specific methods.
Are these estimates medical advice?
No. They are educational calculations.
Why show an average?
It gives a simple summary of the four estimates, but it should not be treated as a validated target.