Compare all four classic IBW formulas — Devine (1974), Robinson (1983), Miller (1983) and Hamwi (1964) — plus the BMI healthy range and adjusted body weight.
Ideal body weight is an estimate of a healthy weight for a given height and sex, computed with one of four classic clinical formulas: Devine (1974), Robinson (1983), Miller (1983) or Hamwi (1964). It was developed for drug dosing and nutritional assessment, not as a fitness or beauty target.
Devine: 45.5 kg + 2.3 kg per inch over 5 feet. A 5'4" woman is 4 inches over 5 feet, so IBW = 45.5 + 2.3 x 4 = 54.7 kg (about 120.6 lb). Robinson gives 55.8 kg, Miller 58.5 kg and Hamwi 54.3 kg for the same height, so the four-formula mean is 55.8 kg.
This calculator uses the four classic IBW formulas (Devine, Robinson, Miller, Hamwi), which are linear functions of height derived from insurance and clinical data. BMI-based ideal weight is instead a range from 18.5 to 24.9 times height squared. Our BMI calculators cover the BMI-range approach; this tool covers the formula approach. Mode 2 shows both side by side so you can compare them.
No single formula is best for everyone. Devine (1974) is the most widely used in hospitals for drug dosing. Robinson (1983) was fitted to newer insurance data and matches a BMI of 22 most closely for men. Miller (1983) usually gives the highest values. Seeing the range across all four is normal — it reflects different source datasets, not an error.
The four classic formulas are only defined for heights of 5 feet (152.4 cm) and above. Below 5 feet this calculator honestly shows each formula's 5-foot baseline (for example 45.5 kg for a woman under Devine) and flags it as undefined rather than extrapolating silently.
Adjusted body weight is a clinical convention used in drug dosing for people whose actual weight differs greatly from IBW: AdjBW = IBW + 0.4 x (actual weight - IBW). Enter your actual weight in Mode 2 to see it computed against the four-formula IBW mean.
IBW formulas ignore muscle mass, frame size, age and body composition, so they should not be used alone as personal targets. Use them as one reference point alongside BMI, waist measurements and professional advice.
No. This tool calculates ideal body weight. For converting between kilograms, pounds, ounces, stones and other units, use our weight converter.
Related tools: BMI calculator · Body frame size · Weight converter
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