Body & Weight
Ideal Weight Calculator
Compare four well-known formulas to see an estimated healthy weight range for your height.
Ideal Weight Calculator Tool
Why 'ideal weight' is really a range
There is no single perfect number that defines everyone's ideal weight — genetics, frame size, muscle mass and body composition all influence what a healthy weight looks like for a given height. What researchers have built instead are several formulas, each developed decades apart for different clinical purposes, that estimate a reasonable target range based on height and sex. This calculator runs your height through four of the most cited formulas at once so you can see the spread rather than relying on just one estimate.
The four formulas explained
The Hamwi formula, created in 1964 for quickly estimating medication dosages, uses a simple per-inch increment above five feet. The Devine formula, from 1974, is still used today to calculate drug dosing in clinical settings and follows a similar structure with slightly different constants. The Robinson formula (1983) and Miller formula (1983) refined these estimates further using updated population data. None of the four was designed as a fitness or aesthetic target — they were built for medical calculations — but together they give a well-triangulated estimate of a reasonable weight range for your height.
What this number does and doesn't tell you
These formulas only use height and sex, so they can't account for whether your weight comes from muscle or fat, your bone density or frame size, or your personal health history. A muscular, athletic person will often weigh more than these formulas suggest while still being perfectly healthy. Use the result as a general reference point for conversations with a healthcare provider, not as a strict number to chase on the scale.
Combining this with other tools
Because ideal weight formulas ignore body composition, it's worth cross-checking your result against your BMI and, ideally, your body fat percentage. If all three paint a similar picture, that's a useful signal. If they disagree significantly, body composition tools like our Body Fat Calculator usually tell a more complete story than weight-only formulas.
Frequently Asked Questions
Which ideal weight formula is most accurate?
No single formula is definitively 'most accurate' since they were all developed for different purposes decades ago. Looking at the average across Hamwi, Devine, Robinson and Miller gives a more balanced estimate than relying on just one.
Why don't these formulas ask about my body frame?
The original formulas only used height and sex for simplicity. Some clinicians manually adjust the result up or down by 10% for small or large body frames, though this isn't part of the original equations.
Is it bad to weigh more than my 'ideal weight' result?
Not necessarily. Muscle mass, bone density and frame size all affect healthy body weight, so many fit, healthy people weigh more than these formulas suggest.
Do these formulas work for children?
No, they were developed and validated for adults only. Pediatric growth charts should be used for children and teenagers instead.
How is this different from BMI?
BMI uses both your height and current weight to classify your existing weight status. Ideal weight formulas use only your height and sex to estimate a target weight range, independent of what you currently weigh.