🎯 Ideal Weight Calculator
Calculate your ideal body weight using scientifically validated formulas including Devine, Robinson, Miller, and Hamwi equations.
Understanding Ideal Weight
Ideal body weight (IBW) is a clinical estimate of what a person should weigh based on their height and gender. While BMI is commonly used for health screening, ideal weight formulas provide a more specific target weight range.
Why Ideal Weight Matters
Knowing your ideal weight helps you:
- Set realistic weight goals - Target a healthy, achievable weight
- Monitor health risks - Deviations from ideal weight may indicate health concerns
- Guide medication dosing - Many drugs are dosed based on ideal body weight
- Assess nutritional status - Used in clinical settings to evaluate patients
Formulas Explained
Devine Formula (1974):
Men: 50 kg + 2.3 kg × (height in inches - 60)
Women: 45.5 kg + 2.3 kg × (height in inches - 60)
Robinson Formula (1983):
Men: 52 kg + 1.9 kg × (height in inches - 60)
Women: 49 kg + 1.7 kg × (height in inches - 60)
Miller Formula (1983):
Men: 56.2 kg + 1.41 kg × (height in inches - 60)
Women: 53.1 kg + 1.36 kg × (height in inches - 60)
Hamwi Formula (1964):
Men: 48 kg + 2.7 kg × (height in inches - 60)
Women: 45.5 kg + 2.2 kg × (height in inches - 60)
Worked Example 1: Male, 5'10" (70 inches)
👨 Example: 70-inch Male
Height: 70 inches (5'10")
Inches over 5 feet: 70 - 60 = 10 inches
| Formula | Calculation | Result |
|---|---|---|
| Devine | 50 + (2.3 × 10) | 73.0 kg (161 lbs) |
| Robinson | 52 + (1.9 × 10) | 71.0 kg (156 lbs) |
| Miller | 56.2 + (1.41 × 10) | 70.3 kg (155 lbs) |
| Hamwi | 48 + (2.7 × 10) | 75.0 kg (165 lbs) |
| Average | - | 72.3 kg (159 lbs) |
Worked Example 2: Female, 5'6" (66 inches)
👩 Example: 66-inch Female
Height: 66 inches (5'6")
Inches over 5 feet: 66 - 60 = 6 inches
| Formula | Calculation | Result |
|---|---|---|
| Devine | 45.5 + (2.3 × 6) | 59.3 kg (131 lbs) |
| Robinson | 49 + (1.7 × 6) | 59.2 kg (130 lbs) |
| Miller | 53.1 + (1.36 × 6) | 61.3 kg (135 lbs) |
| Hamwi | 45.5 + (2.2 × 6) | 58.7 kg (129 lbs) |
| Average | - | 59.6 kg (131 lbs) |
Worked Example 3: Comparing Formulas
📊 Example: Formula Comparison for 6'0" Male
Different formulas can give significantly different results. Here's why the average matters:
| Formula | Ideal Weight | Notes |
|---|---|---|
| Hamwi | 83.2 kg (183 lbs) | Highest estimate; designed for medium frames |
| Devine | 79.6 kg (175 lbs) | Most commonly used in medicine |
| Robinson | 74.8 kg (165 lbs) | Lower estimate; based on Metropolitan Life tables |
| Miller | 73.4 kg (162 lbs) | Lowest estimate; newer formula |
| Range | 73-83 kg | 10 kg (22 lb) difference! |
This shows why using multiple formulas and taking an average provides a more reliable estimate than any single formula.
Limitations
These formulas were developed primarily for medication dosing calculations and may not represent optimal health weights for all individuals. They don't account for:
- Age
- Body composition (muscle vs. fat)
- Frame size
- Ethnicity
- Fitness level
References
- Devine, B. J. (1974). Gentamicin therapy. Drug Intelligence and Clinical Pharmacy, 8(11), 650-655.
- Robinson, J. D., et al. (1983). A meta-analysis of studies on the accuracy of ideal body weight predictions. Journal of Clinical Pharmacy and Therapeutics.
- Hamwi, G. J. (1964). Therapy: changing dietary concepts. In: Diabetes Mellitus: Diagnosis and Treatment. American Diabetes Association.
- Miller, D. R., et al. (1983). Estimating ideal body weight--a new formula. Journal of the American Dietetic Association, 83(6), 729-731.
- CDC. (2025). Healthy Weight. Centers for Disease Control and Prevention.
Disclaimer: These formulas provide estimates for educational purposes. Consult a healthcare provider for personalized advice.