Ideal Body Weight (Miller Formula)

The Miller formula for estimating ideal body weight was published in 1983 by D.R. Miller and colleagues in the American Journal of Hospital Pharmacy. Like the Robinson formula published the same year, the Miller formula was developed as a scientific refinement of the earlier Devine formula, using statistical methods applied to population data to derive coefficients that better predict optimal body weight for a given height. The Miller formula is distinctive for producing the highest ideal weight estimates among the four major IBW formulas, particularly for shorter individuals.

The formula structure follows the same general pattern as other IBW equations: a base weight at 5 feet of height plus an increment per additional inch. For males, Miller uses a base of 56.2 kilograms with a 1.41 kg increment per inch over 60 inches. For females, the base is 53.1 kilograms with a 1.36 kg increment. The notably higher base weights and lower per-inch increments compared to Devine (50/2.3 for males) mean that Miller estimates are higher for people around 5 feet tall but converge with or fall below Devine estimates for people over about 6 feet tall.

Miller derived these coefficients from a broader cross-sectional analysis of population weight-for-height data, aiming to produce estimates that better reflected the actual weight distribution in the general population rather than the idealized weights from insurance tables. This approach inherently captures a slightly larger body habitus as the reference, which some clinicians view as more realistic while others consider it less conservative. The Miller formula is particularly useful as an upper bound when presenting multiple IBW estimates to a patient.

In clinical application, the Miller formula sees its greatest use in comparative analyses where multiple IBW formulas are presented together. Nutrition support teams and clinical dietitians often report Devine, Robinson, Miller, and Hamwi IBW estimates simultaneously to provide a range rather than a single point estimate. The Miller formula's higher values make it particularly useful for patients with larger frames who might feel that Devine or Robinson estimates are unrealistically low for their body type.

This calculator implements the Miller formula with automatic metric-to-imperial conversion. Results include the IBW in both kilograms and pounds, along with a 10% range for frame size variation. The Miller formula is one of four IBW equations available on our platform. For the most comprehensive assessment, use our Ideal Weight Calculator to see all four formulas and their average simultaneously, giving you a well-rounded picture of your ideal weight range.