Ideal Weight Calculator

Calculate your ideal body weight using 4 scientifically validated formulas (Robinson, Miller, Devine, Hamwi) and WHO BMI range. Set healthy weight goals using methods employed by medical professionals.

Recommended Ideal Weight

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What is Ideal Body Weight (IBW)?

Ideal Body Weight (IBW) represents a healthy weight range based on your height, gender, and frame size. Medical professionals use IBW to calculate medication dosages, assess nutritional requirements, and establish healthy weight goals. Multiple scientific formulas have been developed over decades, each taking a slightly different approach but all validated through medical research. These formulas are primarily designed for adults and may require adjustments for special populations like children or athletes.

Devine Formula (1974) - Most Widely Used

The Devine formula was developed in 1974 by Dr. B.J. Devine for calculating medication dosages and remains the most widely used IBW formula in medical practice today. It uses 50 kg at 152.4 cm (5 feet) as the baseline for men and 45.5 kg for women, adding 2.3 kg for each additional 2.54 cm (inch) for both genders. The Devine formula is particularly important in pharmacology and anesthesiology, where many drug dosages are calculated based on ideal body weight rather than actual weight.

Robinson and Miller Formulas (1983)

Published in 1983, both the Robinson and Miller formulas were attempts to refine the Devine formula. The Robinson formula uses 52 kg as the baseline for men with 1.9 kg added per inch, and 49 kg for women with 1.7 kg per inch. The Miller formula uses 56.2 kg baseline with 1.41 kg per inch for men, and 53.1 kg with 1.36 kg per inch for women. These formulas tend to give slightly different results than Devine but are still considered reliable in medical settings.

Hamwi Formula (1964) - The Original

The Hamwi formula, developed by Dr. George J. Hamwi in 1964, is one of the oldest IBW formulas still in use. It uses 48 kg at 152.4 cm (5 feet) for men, adding 2.7 kg per 2.54 cm (inch), and 45.5 kg for women with 2.2 kg per inch added. The Hamwi formula is appreciated for its simplicity and quick calculation, making it useful in clinical settings where rapid assessments are needed. It's particularly popular in nutritional assessments.

BMI vs IBW: What's the Difference?

BMI (Body Mass Index) and IBW (Ideal Body Weight) are two different measurements serving different purposes. BMI is a ratio of weight to height squared, useful for population-level obesity assessments but doesn't account for individual frame size, muscle mass, or bone structure. IBW formulas, on the other hand, provide more personalized estimates by considering gender. The WHO BMI range (18.5-25) applied to your height gives you a healthy weight range, which when used alongside IBW formulas, provides the most accurate picture of your ideal weight target.

Factors Affecting Ideal Weight

Several factors should be considered when determining ideal weight. Frame Size: People have small, medium, or large frames, which can make a 5-10 kg difference in healthy weight range. Muscle Mass: Muscle is denser than fat, so muscular individuals may weigh more than IBW suggests while being very healthy. Age: Body composition changes with aging, with muscle mass typically decreasing. Ethnicity: Research shows different ethnic groups may have slightly different healthy BMI ranges related to health risks. Health Conditions: Certain medical conditions may affect optimal weight targets.