Ideal Body Weight (IBW) Calculator
The Ideal Body Weight (IBW) Calculator estimates an adult's ideal body weight using height and sex. This calculator uses the Devine formula, which is commonly referenced in clinical practice and medical education.
What is Ideal Body Weight?
Ideal Body Weight (IBW) is an estimated weight based mainly on a person's height and sex. It is different from actual body weight and should not be considered a target weight for every individual. Body composition, age, muscle mass, health conditions and other clinical factors can all affect what constitutes a healthy body weight.
In clinical medicine, IBW can be useful as an estimated reference value. It is also discussed in areas such as drug dosing, nutrition assessment and critical care. However, the appropriate weight measure depends on the clinical situation and the medication or treatment being considered.
Devine Formula Used in This Calculator
This calculator uses the Devine formula. For adults, the calculation starts with a base weight and then adds a fixed amount for each inch of height above 5 feet.
| Sex | Devine Formula |
|---|---|
| Male | 50 kg + 2.3 kg for each inch over 5 feet |
| Female | 45.5 kg + 2.3 kg for each inch over 5 feet |
How to Use the IBW Calculator
Select the sex, enter the person's height in centimetres and select Calculate IBW. The calculator converts the height into inches and applies the Devine formula to provide an estimated IBW in kilograms.
Example
For example, an adult male with a height of 170 cm has a height of approximately 66.9 inches. The portion above 5 feet is therefore used in the Devine formula to calculate the estimated ideal body weight.
IBW and Clinical Practice
Ideal body weight is only one of several weight measurements used in healthcare. Depending on the clinical situation, healthcare professionals may also consider actual body weight, adjusted body weight, lean body mass or other measurements.
For medication dosing, the appropriate weight calculation can vary between medicines and patient populations. Therefore, an IBW result should not be used by itself to determine a medication dose.
Important Note
This calculator is intended for educational and general informational use. The Devine formula is an estimation and does not define an individual's medically appropriate weight. It should not replace professional medical assessment or individualized clinical advice.