How to Calculate Your Ideal Body Weight Using 4 Popular Formulas

Ask ten people what their "ideal weight" should be and you will get ten different answers. Ask ten doctors and you might get a broader range — because the concept of an ideal weight has evolved significantly over the past century, and multiple competing formulas exist, each developed from different datasets and population groups.

The four formulas most commonly referenced today are the Hamwi formula (1964), the Devine formula (1974), the Robinson formula (1983), and the Miller formula (1983). All four use height as the primary input, but they differ in their calculation methods and the reference populations they were built on. Understanding where each formula comes from and what it was designed to do will help you interpret the results properly.

Let us walk through each formula, work examples with real height measurements, compare the results side by side, and discuss which formula is most appropriate for different use cases.

Why Multiple Ideal Weight Formulas Exist

Ideal weight formulas grew out of insurance data. In the early 20th century, life insurance companies analyzed mortality data to identify the weight ranges associated with lowest death rates. The idea was simple: find the weight at which people had the longest life expectancy, and call that the "ideal" weight.

The first widely adopted ideal weight tables were published by the Metropolitan Life Insurance Company in 1943 and updated in 1959. These tables provided weight ranges by height and frame size for men and women. They were revolutionary at the time but had significant limitations: they were based exclusively on white American and Canadian policyholders, they used mortality data rather than health data, and they accounted for frame size using a measurement that was difficult to standardize.

Starting in the 1960s, researchers began developing more precise formulas using different reference populations and mathematical approaches. The result was four major formulas, each with its own methodology and slightly different output ranges.

The Hamwi Formula (1964): The Clinical Standard

Dr. G.J. Hamwi, a physician at the University of Iowa, developed his formula in 1964 while working on a clinical guide for assessing healthy body weight. Unlike the Metropolitan Life tables, the Hamwi formula uses a simple linear equation based on height alone and produces a single reference weight rather than a range. It quickly became the most widely used formula in clinical nutrition and remains the default in many hospital systems and dietary reference tools.

Men's Hamwi Formula

Ideal Weight (lbs) = 106 + 6 × (height in inches above 60)

The formula sets a baseline of 106 pounds for a 5-foot-tall man (60 inches) and adds 6 pounds for each additional inch of height. It does not account for frame size, age, or body composition.

Women's Hamwi Formula

Ideal Weight (lbs) = 100 + 5 × (height in inches above 60)

The women's version uses a baseline of 100 pounds for a 5-foot-tall woman and adds 5 pounds per inch of additional height. Hamwi intentionally used a lower baseline and per-inch increment for women based on the population averages available in his 1964 dataset.

Hamwi Example: 5'10" Male

A 5-foot-10-inch man is 70 inches tall — 10 inches above the 60-inch baseline. The calculation: 106 + 6 × 10 = 166 pounds. For a 5'6" woman (66 inches): 100 + 5 × 6 = 130 pounds.

The Devine Formula (1974): ICU and Pharmacology Standard

Dr. B.J. Devine developed his formula in 1974 while working on a textbook chapter for drug dosing in critical care. The formula was designed to estimate "lean body weight" for medication dosage calculations in intensive care settings. Unlike Hamwi, the Devine formula was not intended as a general health screening tool — it was specifically created to help pharmacologists calculate drug doses based on estimated lean tissue mass rather than total body weight.

Men's Devine Formula

Ideal Weight (kg) = 50 + 2.3 × (height in inches above 60)

Baseline is 50 kilograms (approximately 110 pounds) for a 5-foot-tall man, with 2.3 kilograms (approximately 5 pounds) added per inch of height above 5 feet. The formula was derived from data on male hospital patients and was designed to estimate lean (non-fat) body mass.

Women's Devine Formula

Ideal Weight (kg) = 45.5 + 2.3 × (height in inches above 60)

Baseline is 45.5 kilograms (approximately 100 pounds) for a 5-foot-tall woman, with the same 2.3 kilograms per inch increment. Devine used a lower baseline for women based on average lean body mass differences between men and women in his reference population.

Devine Example: 5'10" Male

For the same 5'10" man: 50 + 2.3 × 10 = 73 kilograms, which converts to approximately 161 pounds. This is slightly lower than the Hamwi estimate of 166 pounds because Devine was targeting lean body mass rather than total body weight.

The Robinson Formula (1983): Adjusted for Lean Body Mass

R.H. Robinson and colleagues published their ideal weight formula in 1983 in a study examining body composition and drug dosing. The Robinson formulas are unique in that they use power functions rather than linear relationships, producing slightly curved lines that better reflect the nonlinear relationship between height and healthy body weight across different height ranges.

Men's Robinson Formula

Ideal Weight (kg) = 52 + 1.9 × (height in inches above 60)

Robinson used a baseline of 52 kilograms (114.6 pounds) and a per-inch increment of 1.9 kilograms (4.2 pounds). Compared to Devine, Robinson's formula gives slightly higher weights for taller individuals and slightly lower weights for shorter individuals due to the adjustment in the baseline-to-increment ratio.

Women's Robinson Formula

Ideal Weight (kg) = 49 + 1.7 × (height in inches above 60)

Baseline of 49 kilograms (108 pounds) and increment of 1.7 kilograms (3.7 pounds) per inch. Robinson's women's formula has the highest baseline and lowest per-inch increment of all four formulas, producing the most conservative estimates for women at average heights.

The Miller Formula (1983): The "Average" Formula

Miller, Ginter, and Sargent published their formula in 1983, also focused on body composition assessment for drug dosing. The Miller formulas use a higher baseline and moderate per-inch increments, producing the highest ideal weight estimates of the four formulas for most heights.

Men's Miller Formula

Ideal Weight (kg) = 56.2 + 1.41 × (height in cm above 152.4)

The Miller formula is unusual in that it uses height in centimeters rather than inches and sets the baseline at 56.2 kilograms for a 152.4 cm (5-foot) man, with 1.41 kilograms added for each centimeter above that height. Converted to imperial units, this works out to approximately 1.1 pounds per inch above a baseline of about 112.4 pounds.

Women's Miller Formula

Ideal Weight (kg) = 53.1 + 1.36 × (height in cm above 152.4)

Baseline of 53.1 kilograms for a 152.4 cm (5-foot) woman, with 1.36 kilograms per centimeter. The Miller formula typically produces the highest weight estimates for women among the four formulas, particularly for taller individuals.

Side-by-Side Comparison: All Four Formulas

Let us compare the outputs of all four formulas for the same three heights to see how the results differ:

The range between formulas is not trivial — at 5'10" for men, the spread is 161 to 172 pounds, an 11-pound difference. For women at 5'10", the spread is 150 to 158 pounds. This variation is important context when interpreting ideal weight numbers. No single formula is "correct" — each reflects a different reasonable estimate based on its reference dataset.

BMI-Based Alternative: Using BMI Instead of Height-Only Formulas

An alternative approach to ideal weight estimation is to calculate the weight range that corresponds to a healthy BMI (18.5 to 24.9). This method has become increasingly popular because it integrates weight with height in a standardized way and is endorsed by the WHO and CDC. The Ideal Body Weight Calculator on VivMetric includes both the traditional formulas and the BMI-based range approach.

To calculate your BMI-based healthy weight range, use the BMI formula in reverse. For a 5'10" man (70 inches): the lower bound (BMI 18.5) is (18.5 × 70²) / 703 = 128.5 pounds. The upper bound (BMI 24.9) is (24.9 × 70²) / 703 = 172.5 pounds. This gives a range of roughly 129 to 173 pounds — a much wider range than any single formula provides.

Which Formula Is Best for Whom?

The "best" formula depends on the purpose. Here is a practical guide:

For clinical nutrition counseling: The Hamwi formula is most widely used and recognized by registered dietitians and clinical nutrition programs in the United States. It provides a reasonable single-weight estimate for general healthy population assessment.

For drug dosing in critical care: The Devine formula was specifically designed for this purpose and remains the standard in intensive care unit settings. It estimates lean body mass rather than total weight, making it more appropriate for medication dosage calculations.

For athletes and muscular individuals: No ideal weight formula works well for athletes, because all four formulas assume a typical body composition. If you have significant muscle mass, your "ideal weight" from any formula will underestimate your actual healthy weight. In this case, use the Body Fat Calculator and the Lean Body Mass Calculator for a more appropriate assessment.

For general reference: The BMI-based approach is the most flexible and universally applicable, as it accounts for the full healthy weight range rather than estimating a single number. The Standard Weight Chart provides a quick-reference look-up for healthy weight ranges at common heights.

Important Limitations of All Ideal Weight Formulas

All four formulas share fundamental limitations that are important to understand:

Height-only input: None of the formulas account for body composition, age, sex (beyond the basic male/female split), ethnicity, or activity level. A 5'10" bodybuilder and a 5'10" sedentary office worker would get the same "ideal weight" estimate from every formula.

Population bias: All four formulas were developed using data from Western (primarily American) adult populations. They may not apply directly to individuals from other ethnic or racial backgrounds, or to individuals with atypical body proportions.

Single number vs range: These formulas produce a single target weight, which can be misleading. Healthy weight exists as a range, not a point target. Small variations above or below the formula estimate are not inherently unhealthy.

Outdated reference data: The most recent formula (Miller) dates to 1983. The reference populations are more than 40 years old, and secular changes in body composition mean the formulas may not reflect current population healthy weight ranges.

For a more individualized assessment, combine ideal weight estimates with body fat percentage measurement, waist circumference tracking, and BMI calculation. The Ideal Body Weight Calculator on VivMetric provides all four formula results alongside BMI-based ranges for comparison.

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