Ideal Weight Calculator

About This Tool

The concept of "ideal body weight" has been used in medicine for decades, primarily for drug dosing calculations, nutritional assessments, and setting weight-management goals. This calculator uses four of the most widely referenced formulas in clinical practice, each developed by a different researcher and producing slightly different results.

The Four Formulas Explained

The Devine formula (1974) is the most widely used in healthcare and was originally created to calculate drug dosages for obese patients. It estimates ideal weight as a base amount plus an increment per inch over 5 feet. The Robinson formula (1983) refined Devine's approach with updated population data. The Miller formula (1983) tends to produce slightly higher estimates, making it more realistic for today's population. The Hamwi formula (1964) is the oldest and uses a simpler calculation that was standard practice for decades.

How Frame Size Affects Results

Body frame size accounts for differences in bone structure. A person with a larger skeletal frame naturally carries more weight in bone and supporting tissue. This calculator adjusts ideal weight by approximately 10% up or down based on frame size. The wrist test is a simple way to estimate frame size: wrap your thumb and middle finger around your opposite wrist. Small frames have overlapping fingers, medium frames have fingers that just touch, and large frames have a gap between the fingers.

Why Results Vary Between Formulas

Each formula was developed using different population samples and statistical methods. Rather than relying on a single number, the range across all four formulas gives you a more realistic target zone. The variation between formulas typically spans 10-20 pounds, which reflects the genuine uncertainty in defining a single "ideal" weight for any given height.

Limitations to Consider

These formulas were developed primarily from data on adults of European descent and may not be equally applicable to all ethnicities. They also do not account for age-related changes in body composition, athletic builds, or pregnancy. Body composition measurements like DEXA scans, body fat percentage, or waist-to-height ratio can provide more nuanced health assessments than height-weight formulas alone.