How this calculation works
Compare four historical height-based weight equations rather than treating one number as an ideal body weight. Each starts with a base weight at five feet and adds weight for each extra inch. The average is an arithmetic summary of those four equations, not an independently validated health target. These formulas do not account for your muscle, fat distribution, medical history or goals.
Worked example
This example uses illustrative inputs. Your current result is shown above.
For the male equations at 177.8 cm (70 inches), i = 70 − 60 = 10. Devine gives 50 + 23 = 73 kg; Robinson 52 + 19 = 71 kg; Miller 56.2 + 14.1 = 70.3 kg; Hamwi 48 + 27 = 75 kg. Their average is (73 + 71 + 70.3 + 75) ÷ 4 = 72.325 kg, displayed as 72.3 kg.
Assumptions and limits
- The tool accepts heights of at least 152.4 cm (five feet) and uses the specific rounded coefficients displayed here. It does not extrapolate the equations below their base height.
- The Hamwi calculation uses a rounded kilogram variant. It is not an exact conversion of the original pound-based 106 + 6i (male) or 100 + 5i (female) expressions, so other implementations can differ.
- The four results and their mean are comparisons of historical equations, not prescriptions, medication-dosing instructions or proof of a healthy weight.
Questions people ask
Which of the four weights should I aim for?
The calculator cannot choose a personal target. The spread shows how much these historical formulas differ even for the same height; clinical context matters more than choosing their mean.
Why is another Hamwi calculator slightly different?
Some tools calculate in pounds and convert exactly; this one uses the explicitly listed rounded kilogram coefficients. Neither rounding choice makes the result a personalised recommendation.
Why does the tool reject a height below five feet?
The implemented equations use inches above a five-foot base. Rather than silently extrapolating below that base, this tool limits the supported height range.