Ideal Weight Is an Estimate, Not a Diagnosis
Historical ideal-weight equations produce separate height-based point estimates. They do not prescribe a target, define a universal healthy range, diagnose health, or measure body composition.
Open Ideal Weight Calculator
Quick answer
In short
- What the tool returns: Devine, Robinson, Miller, and Hamwi are displayed as four separate historical point estimates.
- What it does not return: The estimates are not one reference range, a prescribed target, or a diagnosis.
- Important context: The equations come from different historical contexts and do not directly account for body composition or fat distribution.
The frozen Ideal Weight Calculator uses height and a selected historical male or female equation set to display separate Devine, Robinson, Miller, and Hamwi estimates. It does not average them or turn their spread into a medically recommended range.
Use the calculators: Compare estimates with the Ideal Weight Calculator, BMI Calculator, and Body Fat Calculator.
Historical point estimates, not one healthy range
These equations were developed in different historical clinical or actuarial contexts and use different base values and per-inch additions. Their original purposes were not identical. Historical use does not make any output a current personalised health target, and no one estimate is correct for every person.
What is known about formula provenance
Robinson and colleagues published their equation in work on ideal body weight for drug-dosage calculations. That specific context should not be assigned to every displayed equation. Where an exact original purpose is not firmly established, it is more accurate to describe the equation only as historical.
How to read the four results
- Read Devine, Robinson, Miller, and Hamwi as separate comparison values.
- Do not average them into a medically recommended target.
- Do not treat their spread as a universal healthy range.
- Do not use a formula result as a diagnosis, body-composition measurement, or medication-dosing instruction.
Body composition and individual context
Height-only formulas do not directly account for muscle, fat, bone, frame, fat distribution, disability, major body-composition differences, significant illness, medications, or other clinical information. Two people at the same height can therefore receive the same formula estimate while having different health needs.
Age, pregnancy, and breastfeeding boundaries
The historical equations are not designed to prescribe targets for people under 18. Pregnancy and breastfeeding can change appropriate weight assessment, so a historical point estimate should not be used as a pregnancy or postpartum target.
Unexpected weight loss and eating-disorder safety
Unexpected or unexplained weight loss can warrant professional assessment. A formula result should not be used to justify extreme dieting, rapid weight change, or ignoring clinical advice. Eating-disorder concerns require more than a calculator result; seek qualified support when eating, body image, or compensatory behaviours are causing distress or harm.
Modern planning is a separate task
Evidence-based planning tools can model changes in energy intake and activity, but that does not validate historical ideal-weight equations or turn their estimates into treatment targets. Individual planning may require a health professional, especially when illness, pregnancy, breastfeeding, unexpected weight loss, or eating-disorder concerns apply.
Source links for this Guide were verified on 2026-07-26.
Reference check
Sources and references
These references provide background context for the topic. They do not replace professional advice or official documents.
- Ideal body weight: A commentary
Chichester, Holmes and Hubbard; Clinical Nutrition ESPEN
- Universal equation for estimating ideal body weight and body weight at any BMI
Peterson, Thomas, Blackburn and Heymsfield; American Journal of Clinical Nutrition
- Determination of ideal body weight for drug dosage calculations
Robinson and colleagues; American Journal of Hospital Pharmacy
- Ideal body weight calculations: fit for purpose in modern anaesthesia?
Appelbaum and Clarke; European Journal of Anaesthesiology
- About the Body Weight Planner
National Institute of Diabetes and Digestive and Kidney Diseases
- Unintentional weight loss
MedlinePlus
- Eating Disorders: What You Need to Know
National Institute of Mental Health
Historical ideal-weight equations provide separate point estimates, not a diagnosis, prescribed target, or universal healthy range.
Use the tool instead
Use the matching calculator when you want to plug in your own numbers and get a result faster.
Open Calculator