Ideal Weight Calculator
This professional-grade ideal weight calculator estimates a reference body weight from height and sex using the Devine, Hamwi, Robinson, and Miller equations. It’s designed for adults, supports metric and US units, and also displays a healthy BMI-based weight range for context.
Calculator
Results
These adult estimates are informative only and not a medical diagnosis. Body composition, age, and clinical factors matter.
Data Source and Methodology
Authoritative reference: Pai MP, Paloucek FP. “The Origin of the ‘Ideal’ Body Weight Equations.” The Annals of Pharmacotherapy. 2000;34(9):1066–1069. Published: 2000. Direct link: PubMed 10981214.
Healthy BMI range references: World Health Organization (WHO) BMI classification: WHO: Obesity and overweight.
Tutti i calcoli si basano rigorosamente sulle formule e sui dati forniti da questa fonte.
The Formula Explained
Let h be total height in inches, and Δ = h − 60 (inches over 5 ft; negative if below).
Female:
Devine: \( \text{IBW}_{F} = 45.5 + 2.3\,\Delta \)
Hamwi: \( \text{IBW}_{F} = 45.5 + 2.2\,\Delta \)
Robinson: \( \text{IBW}_{F} = 49.0 + 1.7\,\Delta \)
Miller: \( \text{IBW}_{F} = 53.1 + 1.36\,\Delta \)
Male:
Devine: \( \text{IBW}_{M} = 50.0 + 2.3\,\Delta \)
Hamwi: \( \text{IBW}_{M} = 48.0 + 2.7\,\Delta \)
Robinson: \( \text{IBW}_{M} = 52.0 + 1.9\,\Delta \)
Miller: \( \text{IBW}_{M} = 56.2 + 1.41\,\Delta \)
Healthy BMI range weights at height H (meters): \( W = \text{BMI} \times H^2 \), with BMI ∈ [18.5, 24.9].
Glossary of Variables
- Sex: Biological sex used by source equations (female, male).
- Height: Stature of the person. Accepted in centimeters or feet/inches.
- Δ (Delta): Inches above or below 5 feet (60 inches).
- IBW: Ideal Body Weight returned by Devine, Hamwi, Robinson, or Miller. Reported in kg and lb.
- Average: Mean of the four IBW results.
- Range: Minimum to maximum across the four IBW results.
- Healthy BMI weight range: Weight interval that yields BMI 18.5–24.9 for the given height.
Worked Example
How it Works: A Step-by-Step Example
Scenario: Adult male, height 178 cm.
- Convert height to inches: 178 ÷ 2.54 = 70.08 inches. Δ = 70.08 − 60 = 10.08 inches.
- Devine (male): 50.0 + 2.3×10.08 = 73.18 kg.
- Hamwi (male): 48.0 + 2.7×10.08 = 75.22 kg.
- Robinson (male): 52.0 + 1.9×10.08 = 71.15 kg.
- Miller (male): 56.2 + 1.41×10.08 = 70.42 kg.
- Average ≈ (73.18 + 75.22 + 71.15 + 70.42) / 4 = 72.49 kg.
- Healthy BMI 18.5–24.9 at 1.78 m: 18.5×1.78² = 58.6 kg to 24.9×1.78² = 78.8 kg.
This example illustrates why reporting a range and an average provides a more useful target than a single value.
Frequently Asked Questions (FAQ)
Which ideal weight formula should I trust?
No single equation is universally superior. Devine and Hamwi are common in clinical dosing; Robinson and Miller are later refinements. Reviewing all four provides a sensible range.
Is ideal weight the same as BMI?
No. Ideal weight equations estimate a reference body weight from height and sex. BMI classifies weight status from weight/height². Both are shown here for context.
Are these formulas valid for children or pregnancy?
No. They are intended for non-pregnant adults. Children and pregnant individuals require specialized references.
Do I need to select sex? Why?
Yes. The source equations are sex-specific due to body composition differences observed in the derivation datasets.
What if I’m very muscular or an athlete?
Muscular individuals may weigh more than these estimates while remaining healthy. Consider body fat measurement and professional guidance.
What units can I use?
Metric (cm/kg) and US customary (ft/in, lb). The tool converts automatically.
Can I download or share my results?
You can copy the results displayed on screen. A PDF/print view will be available in future updates.