What ideal-body-weight formulas do—and do not—mean
Compare four historical height-based “ideal body weight” formulas and the weights corresponding to BMI 18.5–24.9.
This page provides an equation-based estimate for education and planning. It does not diagnose a condition, measure an individual response, or replace professional care.
How to use this health calculator
- Choose appropriate inputs: Enter measurements using the units and ranges shown.
- Review the assumptions: Confirm that the model applies before interpreting the result.
- Calculate and interpret: Read the result together with its limitations and cautions.
- Use professional guidance when needed: Do not use a general calculator to change medication, treatment, or a clinician-directed plan.
Formula and variables
The formulas use only height and a binary equation input. They were not designed to identify a personally ideal appearance, health outcome or weight-loss target.
Each formula starts with a sex-specific weight at 5 feet and adds a fixed amount per inch above 5 feet; BMI reference weights = BMI × height²- H — Height above 5 feet
- Inches above 60 inches, after unit conversion.
- S — Equation sex input
- Selects the historical sex-specific constants.
Worked example: Devine male equation at 5 ft 10 in
A user selects the male equation and enters 70 inches.
- Height
- 5 ft 10 in
- 10 inches above 5 feet.
- Devine: 50 + 2.3 × 10 = 73 kg.
Result: The Devine reference is 73 kg; other equations return different values.
Disagreement between formulas demonstrates model uncertainty rather than a true ideal weight.
Understanding your results
Equation result
The numerical output follows the displayed formula and entered assumptions.
Personal interpretation
Individual biology, measurement error, environment, health conditions and medicines can change real-world outcomes.
Assumptions
- The calculator is used for an adult at least 5 feet tall.
- Height is entered accurately in the selected units.
- The user understands these are historical reference equations.
Limitations
- The formulas ignore age, frame size, muscle mass, body composition, ethnicity, pregnancy and health conditions.
- The term “ideal” is historical and should not be interpreted as an appearance standard or guaranteed healthy weight.
- BMI reference weights inherit the limitations of BMI.
- Clinical uses such as drug dosing may specify a particular equation and additional rules.
Common mistakes
- Averaging formulas and treating the result as a required target.
- Using these adult equations for children or pregnancy.
- Assuming the binary equation input describes gender identity.
- Changing medicine doses from a public calculator result.
Practical use cases
Educational estimate
Explore how the inputs affect the equation result.
Consistent tracking
Compare estimates only when methods, units and conditions are consistent.
Planning and decision guide
Treat cautions as part of the result
Weight-related care should consider health history, body composition, function, nutrition and personal circumstances—not a single equation.
Do not use these results to support unsafe restriction, purging or compulsive exercise; seek qualified support for eating or body-image concerns.
Escalate symptoms or clinical questions
Seek qualified medical advice for symptoms, diagnosed conditions, medicines, pregnancy, or individualized treatment decisions.
Frequently asked questions
Which ideal-weight formula is best?
None is universally best. Use the exact equation required by a legitimate protocol, or treat the comparison as educational.
Why do results differ?
Each formula uses different constants and was developed for different historical purposes.
Can this set a medication dose?
No. Medication dosing requires the prescribed protocol and professional verification.
Sources and review
- Ideal Body Weight: A Commentary — Clinical Nutrition ESPEN via PubMed Central. Accessed 2026-08-03.
Reviewed 2026-08-03.