The Devine Formula is one of the most commonly used methods to estimate Ideal Body Weight (IBW) in clinical nutrition and dietetics. It was originally developed to help determine appropriate medication dosages, but today it's widely used as a reference point for healthy weight ranges.
Unlike BMI, which uses total body weight, the Devine formula is based primarily on height and sex, making it a simple and practical tool in clinical settings.
The Devine Formula
Women: IBW = 45.5 + 2.3 × (inches over 5 feet)
Step-by-Step Example
Let's calculate IBW for a woman who is 5'6" (66 inches) tall.
Step 2 — Multiply: 2.3 × 6 = 13.8
Step 3 — Add base weight (female): 45.5 + 13.8 = 59.3 kg
The calculator above also shows a ±10% healthy range (53.4 – 65.2 kg in this example) since IBW is a reference midpoint, not a single target number.
How Does the Devine Formula Compare?
Several IBW formulas exist. The Devine is the most commonly cited in clinical nutrition:
| Formula | Men (base) | Women (base) | Per inch over 5 ft |
|---|---|---|---|
| Devine ⭐ | 50 kg | 45.5 kg | +2.3 kg |
| Robinson | 52 kg | 49 kg | +1.9 kg (M) / +1.7 kg (F) |
| Miller | 56.2 kg | 53.1 kg | +1.41 kg (M) / +1.36 kg (F) |
Limitations of IBW
- Does not account for body composition or muscle mass
- May be inaccurate for people under 5 feet tall (below its valid range)
- Does not consider age, ethnicity, or frame size
- Originally designed for pharmacological dosing, not personal weight goals
Final Note
The Devine formula is a helpful reference, but it should not be interpreted as a strict target weight. In practice, it's best used as a guideline within a broader assessment, alongside BMI, body fat percentage, and overall health goals.