Ideal Body Weight

What This Calculator Measures

Estimates ideal body weight using the Devine formula, providing a size-adjusted reference weight used in drug dosing and physiological comparisons.

How to Use

1. Select the patient's sex.
2. Enter height in centimeters.
3. Review the estimated ideal body weight in kg.

Interpretation Guide

IBW provides a reference weight for a given height and sex; it does not define health or body composition. It is commonly used as the weight basis for certain drug-dosing calculations and for deriving adjusted body weight.

Clinical Significance

IBW is the foundation for several weight-based dosing adjustments, particularly adjusted body weight in obese patients, and is widely used in clinical pharmacy and dosing practice.

When to Use

• As a size-adjusted weight for drug dosing
• Calculating adjusted body weight for dosing in obesity
• Comparing patient weight against a height-based reference

When Not to Use

• To diagnose obesity or underweight — use BMI
• As a target weight for weight-loss programs
• In children, where age- and height-based references are needed
• In patients with major amputations without adjustment

Limitations

• The Devine formula was derived for adults and is not validated in children.
• May underestimate for patients with high lean mass and overestimate in other body types.
• IBW is a mathematical reference, not a measure of health.
• Different formulas (Devine, Robinson, Miller, Hamwi) yield different values.

Worked Example

A 35-year-old man is 180 cm tall.

IBW = 50 + 2.3 × (180/2.54 − 60) ≈ 75.0 kg using the Devine formula.

Evidence

Source

Internal Medicine / Pharmacy

Reference

Devine BJ. Drug Intell Clin Pharm. 1974;8(11):650-655.

Reviewed By

MedCalcHub Clinical Team

Version

1974

Updated

2026-08

1. Devine BJ. Drug Intell Clin Pharm. 1974;8(11):650-655.

References

1. Devine BJ. Gentamicin therapy. Drug Intell Clin Pharm. 1974;8(11):650-655. (Original Description)