Data Source & Methodology
Authoritative sources:
- Devine BJ. “Gentamicin therapy.” Drug Intelligence & Clinical Pharmacy 1974;8:650–655. (Devine IBW). Reference. :contentReference[oaicite:0]{index=0}
- Hamwi GJ (1964). Frame-size IBW tables (commonly summarized as 106 lb + 6 lb/in for men; 100 lb + 5 lb/in for women). Summary: PEN Group briefing. :contentReference[oaicite:1]{index=1}
- Robinson JD et al. (1983) and Miller DR et al. (1983) formulas summarized in comparative reviews (e.g., Pai & Paloucek 2000) and calculators. See Robinson, Miller. :contentReference[oaicite:2]{index=2}
- Healthy BMI range (adults): WHO/CDC 18.5–24.9 kg/m². CDC, WHO. :contentReference[oaicite:3]{index=3}
- BMI midpoint formula IBW = 22 × H² (m). Brodsky J. Obesity Surgery 2005. Summary: paper note. :contentReference[oaicite:4]{index=4}
Tutti i calcoli si basano rigorosamente sulle formule e sui dati forniti da queste fonti.
The Formula Explained
Devine (kg): for men \( IBW = 50 + 2.3 \times (inches - 60) \);\n for women \( IBW = 45.5 + 2.3 \times (inches - 60) \).
Hamwi (lb): men \( 106 + 6 \times (inches - 60) \), women \( 100 + 5 \times (inches - 60) \); convert to kg by dividing by \(2.20462\).
Robinson (kg): men \( 52 + 1.9 \times (inches - 60) \), women \( 49 + 1.7 \times (inches - 60) \).
Miller (kg): men \( 56.2 + 1.41 \times (inches - 60) \), women \( 53.1 + 1.36 \times (inches - 60) \).
BMI midpoint: \( IBW = 22 \times H^2 \) where \( H \) is height in meters.
Healthy BMI range: \( [18.5 \times H^2,\; 24.9 \times H^2] \).
Adjusted Body Weight (ABW) (when actual ≥120% of IBW): \( ABW = IBW + 0.4\,(W_{actual} - IBW) \).
Glossary of Inputs & Outputs
| Name | Symbol | Definition | Units |
|---|---|---|---|
| Height | H | Stature used by height-based IBW equations | cm / ft,in |
| Sex | — | Selects sex-specific coefficients in the equations | — |
| Actual weight | Wactual | Optional; used to compute ABW in obesity dosing contexts | kg / lb |
| Ideal body weight | IBW | Height-based estimate (Devine/Hamwi/Robinson/Miller/BMI22) | kg |
| Healthy weight range | — | WHO/CDC BMI 18.5–24.9 converted to kg for your height | kg |
| Adjusted body weight | ABW | Weighted blend of IBW and actual when ≥120% IBW | kg |
How It Works: A Step-by-Step Example
Example
Sex: male; Height: 175 cm (1.75 m = 68.90 in). Primary formula: Devine.
- Convert height to inches over 5 ft: \( 68.90 - 60 = 8.90 \) in.
- Devine (male): \( IBW = 50 + 2.3 \times 8.90 = 70.47\text{ kg} \).
- BMI range: \( H^2 = 1.75^2 = 3.0625 \). Healthy range = \( [18.5 \times 3.0625,\; 24.9 \times 3.0625] = [56.7,\; 76.3]\text{ kg} \).
Frequently Asked Questions
Is “ideal weight” the same as “healthy weight”?
No. IBW formulas give a single height-based estimate. Healthy weight is a range based on BMI cut-offs; clinical context matters. CDC/WHO define adult “healthy” as BMI 18.5–24.9. :contentReference[oaicite:5]{index=5}
Which formula is most used clinically?
Devine is widely used for medication dosing in adults; Robinson and Miller are alternatives. Always follow local protocols. :contentReference[oaicite:6]{index=6}
Why do formulas disagree?
They come from different datasets and eras; coefficients vary by sex and inches above 5 ft, leading to small systematic differences.
Does BMI have limitations?
Yes—BMI doesn’t distinguish fat from muscle and may misclassify athletes or older adults. New proposals emphasize waist measures and clinical complications alongside BMI. :contentReference[oaicite:7]{index=7}
Can I use this for children?
No. Use BMI-for-age percentiles (2–19 years). Adult formulas are not appropriate.
Tool developed by Ugo Candido. Content medically cross-checked against cited sources.
Last accuracy review: