Ideal Weight Calculator

How This Calculator Works

An “ideal weight” formula estimates a reference body weight from height and gender, using a linear relationship first published decades ago for clinical use. Enter your gender at birth and height, and this calculator shows the result from four different published formulas side by side — plus their average — since no single formula is more “correct” than the others.

Showing all four is deliberate: each was developed independently by a different research group at a different time, and they don’t agree exactly. Presenting just one as a single definitive number would overstate how precise this kind of estimate actually is.

The Formula

Every formula below shares the same shape: a base weight at exactly 5 feet (60 inches) tall, plus a fixed rate for every inch above or below that — so the same one color tracks the same one variable (inches over 5 ft) across all four:

$$\vB{\text{Devine (1974), Men}} = 50.0 + 2.30 \times \vA{\text{Inches Over 5 Ft}} \text{ kg}$$ $$\vB{\text{Devine (1974), Women}} = 45.5 + 2.30 \times \vA{\text{Inches Over 5 Ft}} \text{ kg}$$ $$\vC{\text{Robinson (1983), Men}} = 52.0 + 1.90 \times \vA{\text{Inches Over 5 Ft}} \text{ kg}$$ $$\vC{\text{Robinson (1983), Women}} = 49.0 + 1.70 \times \vA{\text{Inches Over 5 Ft}} \text{ kg}$$ $$\vD{\text{Miller (1983), Men}} = 56.2 + 1.41 \times \vA{\text{Inches Over 5 Ft}} \text{ kg}$$ $$\vD{\text{Miller (1983), Women}} = 53.1 + 1.36 \times \vA{\text{Inches Over 5 Ft}} \text{ kg}$$ $$\vE{\text{Hamwi (1964), Men}} = 48.0 + 2.70 \times \vA{\text{Inches Over 5 Ft}} \text{ kg}$$ $$\vE{\text{Hamwi (1964), Women}} = 45.5 + 2.20 \times \vA{\text{Inches Over 5 Ft}} \text{ kg}$$

The Devine formula was originally created for drug-dosing calculations, not general wellness, but is the most widely cited of the four today. Robinson and Miller are both later independent revisions of Devine using updated population data; Hamwi is the oldest, originally a quick bedside estimate for nutrition planning. This calculator’s headline number is the plain average of all four.

Worked Example

A man who is 5’10” (177.8 cm) tall — 10 inches over the 5-foot base:

1. Devine: $50 + 2.3 \times \vA{10} = \vB{73} \text{ kg}$
2. Robinson: $52 + 1.9 \times \vA{10} = \vC{71} \text{ kg}$
3. Miller: $56.2 + 1.41 \times \vA{10} = \vD{70.3} \text{ kg}$
4. Hamwi: $48 + 2.7 \times \vA{10} = \vE{75} \text{ kg}$
5. Average: $(\vB{73} + \vC{71} + \vD{70.3} + \vE{75}) \div 4 = 72.325 \text{ kg}$ (about 159.5 lb).