Devine, Robinson, Miller, and Hamwi were all built for clinical dosing, not personal targets — seeing all four side by side (and their average) is more useful than trusting any single one.
Devine (1974), Robinson (1983), Miller (1983), and Hamwi (1964) were each derived from different population samples at different times, mostly to standardize medication dosing (many drug doses scale with body weight, and clinicians needed a consistent reference weight rather than a patient's actual, more variable weight). They broadly agree but never match exactly — the spread between them is the honest range of uncertainty in any single "ideal weight" number, not a sign that one formula is more correct than another.
Strictly, none of them for personal health goals — they exist for clinical dosing calculations, not as targets to diet toward. The average of all four gives a reasonable single reference point, but the healthy BMI weight range shown above is the more defensible general-purpose answer, since it's a range (reflecting that a healthy weight varies by frame and build) rather than a falsely precise single number.
No — all four use only height and sex, the same core limitation BMI has. A muscular or large-framed person will compute a lower "ideal weight" than is actually healthy for their build, since none of these formulas can distinguish muscle from fat or account for bone structure.
Devine: 50 kg + 2.3 kg per inch over 5 feet (men); 45.5 kg + 2.3 kg per inch over 5 feet (women). The most widely used in clinical practice today, especially for drug dosing.
Robinson: 52 kg + 1.9 kg per inch over 5 feet (men); 49 kg + 1.7 kg per inch over 5 feet (women). A 1983 refinement of Devine using a larger dataset.
Miller: 56.2 kg + 1.41 kg per inch over 5 feet (men); 53.1 kg + 1.36 kg per inch over 5 feet (women). Tends to produce the highest estimates of the four.
Hamwi: 48 kg + 2.7 kg per inch over 5 feet (men); 45.5 kg + 2.2 kg per inch over 5 feet (women). The oldest of the four, originally a quick mental-math rule of thumb for clinicians.
BMI works backward from a healthy range (18.5–24.9) to a weight range for your height, which is a fundamentally different approach from these four formulas — it doesn't target one "ideal" number, just a band. Use the BMI Calculator for that range-based view, and treat this page's four formulas as clinical reference points for comparison, not competing "correct" answers.
No — all four were derived from adult populations of typical height ranges; a pediatrician's growth chart is the correct tool for a child's healthy weight. At the extremes of adult height, all four formulas become less reliable, since none were validated on those populations specifically.
Worked example: a 5'7" (170 cm) man — 7 inches over 5 feet: Devine = 50 + 2.3×7 = 66.1 kg; Robinson = 52 + 1.9×7 = 65.3 kg; Miller = 56.2 + 1.41×7 = 66.1 kg; Hamwi = 48 + 2.7×7 = 66.9 kg. Average ≈ 66.1 kg (145.7 lb) — and his healthy BMI weight range at 170 cm is roughly 53.5–72.0 kg, comfortably containing all four estimates.