Free Health Calculator

Ideal Weight Calculator — find your target

Calculate your ideal body weight range using four proven medical formulas.

Calculate Ideal Weight ↓

Enter your details

Results shown for four widely-used formulas: Devine, Robinson, Miller, and Hamwi.

average ideal weight (kg)

Results by formula:

Devine
Robinson
Miller
Hamwi

Calories & Macros

My ideal weight estimate

kg (average of 4 formulas)

Devine

Hamwi

calories-macros.com

Which formula should you use?

Devine

Most widely used

Developed in 1974 by Dr. B.J. Devine, originally to help calculate drug dosages for obese patients where standard weight-based dosing didn't apply well. It remains the most commonly referenced formula in clinical and pharmacy settings today, decades after its original narrow purpose.

Robinson

Updated Devine

A 1983 revision by Robinson et al. that produces slightly lower estimates than Devine, based on a larger and more representative dataset of the era. Many clinicians consider it a modest improvement, though the difference from Devine is usually only a kilogram or two.

Miller

Lower estimates

Published in 1983, the Miller formula tends to give the lowest estimates among the four, particularly for taller individuals. Some researchers argue it better reflects realistic, sustainable body weights rather than a narrower clinical ideal.

Hamwi

Frame-based

Created by Dr. George Hamwi in 1964, this formula is often used as a starting baseline, then manually adjusted ±10% for small or large body frame size — something the other three formulas don't account for directly, which is why results can vary between formulas for the same person.

Why four formulas give four different answers

All four formulas share the same basic approach: they were built by fitting a straight-line equation to height-weight data from specific study populations, decades ago. None of them account for muscle mass, bone density, age, or body fat distribution — they only use height and gender as inputs. That's why we show an average across all four rather than picking a single 'correct' number: the spread between them (often 3-5 kg) is a more honest picture than false precision from just one formula.

These formulas are best treated as a rough starting reference, not a strict target. A muscular, athletic person will likely weigh more than any of these formulas suggest and still be perfectly healthy. If you want a measure that reflects body composition rather than just a height-based estimate, pair this result with our BMI Calculator and Body Fat Percentage Calculator for a fuller picture.

Frequently asked questions about ideal weight

None is definitively 'most accurate' since they were each derived from different populations decades ago and none accounts for body composition. Robinson is often cited as a modest refinement of Devine, but in practice the average across all four is more useful than picking one as authoritative.
These specific formulas don't factor in age directly, but in practice a healthy weight range can shift slightly for older adults — some research suggests a modestly higher BMI may be protective after age 65. If you're over 65, treat the result here as a general reference rather than a strict target.
Frame size refers to your skeletal structure — small, medium, or large — usually estimated from wrist circumference relative to height. A common rule of thumb: measure your wrist circumference in cm; if it's proportionally small relative to your height you have a small frame, and the Hamwi formula result should be adjusted down by about 10%, or up by 10% for a large frame.
No — think of it as a reasonable range rather than a precise target. Health outcomes depend far more on body composition, fitness level, and metabolic markers (blood pressure, blood sugar) than on hitting an exact number derived from a decades-old formula based only on your height and gender.

Related tools