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⚖️ Hamwi Ideal Weight Calculator

Calculate your ideal body weight using the classic Hamwi formula

Your Information
Hamwi uses different formulas for men and women
cm
kg
For comparison with ideal weight
Hamwi Formula

Men: 48 kg + 2.7 kg per inch over 5 feet

Women: 45.5 kg + 2.2 kg per inch over 5 feet

Quick Reference
Hamwi Formula (1964)

Developed by Dr. G.J. Hamwi for medication dosing, now widely used in clinical and fitness settings.

Applications:
  • Medical dosing calculations
  • Nutritional assessments
  • Weight loss goal setting
  • Fitness planning
  • Clinical evaluations
Learn More

AHA: Heart Health & Fitness

CDC: Healthy Weight Range

Mayo Clinic: Weight Management

Related Calculators

🌟 Key Features

  • Classic Formula: Proven Hamwi method from 1964, still widely used today
  • Gender-Specific: Different calculations for men and women
  • Quick Results: Simple height-based calculation
  • Weight Range: Provides ±10% variance for healthy range
  • Current Weight Comparison: See how you compare to ideal
  • Dual Units: Support for metric (cm/kg) and imperial (ft/in/lbs)
  • BMI Calculation: Shows BMI at ideal weight
  • Free to Use: No registration required

📋 How to Use the Hamwi Calculator

  1. Select Gender: Choose male or female (formula differs by gender)
  2. Choose Units: Select metric (cm/kg) or imperial (ft/in/lbs)
  3. Enter Height: Input your height accurately
  4. Add Current Weight (Optional): Enter for comparison with ideal
  5. Calculate: View your ideal weight and healthy range

🔍 Understanding the Hamwi Formula

👨 For Men

48 kg + 2.7 kg per inch over 5 feet

Example: Man who is 5'10" (70 inches)

  • Height over 5 feet: 10 inches
  • 48 + (2.7 × 10) = 48 + 27 = 75 kg (165 lbs)
  • Healthy range: 67.5 - 82.5 kg (149 - 182 lbs)
👩 For Women

45.5 kg + 2.2 kg per inch over 5 feet

Example: Woman who is 5'6" (66 inches)

  • Height over 5 feet: 6 inches
  • 45.5 + (2.2 × 6) = 45.5 + 13.2 = 58.7 kg (129 lbs)
  • Healthy range: 52.8 - 64.6 kg (116 - 142 lbs)
📊 The ±10% Range

The Hamwi formula provides a single "ideal" weight, but individual variations in body composition, frame size, and muscle mass mean a range is more realistic. The ±10% variance accounts for these differences while maintaining healthy body composition. This range is widely accepted in medical and nutritional practice.

🧮 Step-by-Step Calculation Examples

Height: 5 feet 4 inches = 64 inches total

Calculation:

  1. Height over 5 feet: 64 - 60 = 4 inches
  2. Base weight for women: 45.5 kg
  3. Add: 2.2 kg × 4 inches = 8.8 kg
  4. Ideal weight: 45.5 + 8.8 = 54.3 kg (120 lbs)
  5. Healthy range: 48.9 - 59.7 kg (108 - 132 lbs)

Interpretation: A 5'4" woman should aim for around 54 kg, with a healthy range between 49-60 kg depending on frame size and muscle mass.

Height: 6 feet 0 inches = 72 inches total

Calculation:

  1. Height over 5 feet: 72 - 60 = 12 inches
  2. Base weight for men: 48 kg
  3. Add: 2.7 kg × 12 inches = 32.4 kg
  4. Ideal weight: 48 + 32.4 = 80.4 kg (177 lbs)
  5. Healthy range: 72.4 - 88.4 kg (160 - 195 lbs)

Interpretation: A 6'0" man should target approximately 80 kg, with acceptable range of 72-88 kg. Athletes with higher muscle mass may be at the upper end or slightly above.

Height: 5 feet 8 inches = 68 inches total

Calculation:

  1. Height over 5 feet: 68 - 60 = 8 inches
  2. Base weight for women: 45.5 kg
  3. Add: 2.2 kg × 8 inches = 17.6 kg
  4. Ideal weight: 45.5 + 17.6 = 63.1 kg (139 lbs)
  5. Healthy range: 56.8 - 69.4 kg (125 - 153 lbs)

Interpretation: A 5'8" woman's ideal weight is around 63 kg. The range accounts for different body types - smaller frames closer to 57 kg, larger frames or athletic builds up to 69 kg.

⚖️ Hamwi vs. Other IBW Formulas

Formula Year Male (5'10") Female (5'6") Best For
Hamwi 1964 75 kg (165 lbs) 58.7 kg (129 lbs) Quick estimates, medication dosing
Devine 1974 77.1 kg (170 lbs) 59.9 kg (132 lbs) Pharmacy calculations
Robinson 1983 75.7 kg (167 lbs) 59.4 kg (131 lbs) General population
Miller 1983 76.3 kg (168 lbs) 58.1 kg (128 lbs) Nutritional assessment
BMI 22 - 73.5 kg (162 lbs) 60.1 kg (132 lbs) WHO recommendations
📝 Important Note

All IBW formulas provide estimates based on height and gender only. They don't account for body frame size, muscle mass, bone density, or individual body composition. Use IBW as a general guideline, not an absolute target. Consult healthcare providers for personalized weight goals.

🌍 Real-World Applications

🏥 Medical Uses
  • Medication Dosing: Many drugs are dosed based on IBW, especially for obese patients
  • Ventilator Settings: Tidal volume calculations in ICU
  • Nutritional Support: Caloric needs for tube feeding or TPN
  • Dialysis: Determining dry weight targets
  • Anesthesia: Drug calculations for surgery
  • Clinical Assessments: Evaluating malnutrition or obesity
💪 Fitness & Wellness
  • Weight Loss Goals: Setting realistic target weights
  • Fitness Planning: Determining healthy weight for athletic performance
  • Nutrition Plans: Baseline for calculating macros and calories
  • Progress Tracking: Monitoring weight changes over time
  • Body Composition: Reference point for lean mass assessments
  • Health Screening: Quick assessment tool for general wellness

⚠️ Limitations of the Hamwi Formula

❌ Does NOT Account For:
  • Body frame size (small, medium, large)
  • Muscle mass vs. fat mass
  • Bone density variations
  • Age-related changes
  • Ethnicity differences in body composition
  • Athletic build or bodybuilding
  • Individual metabolic differences
  • Medical conditions affecting weight
✅ Best Practices:
  • Use as a starting point, not absolute goal
  • Consider the ±10% range for individual variation
  • Combine with body composition analysis
  • Account for frame size (wrist/elbow measurements)
  • Consult healthcare provider for medical applications
  • Focus on body composition over weight alone
  • Track multiple health metrics (waist, BMI, body fat%)
  • Adjust for athletic or sedentary lifestyles

❓ Frequently Asked Questions

The Hamwi formula is accurate as a general estimate for ideal body weight based on height and gender. It's been validated in medical settings and correlates well with healthy BMI ranges (18.5-24.9). However, it doesn't account for individual factors like muscle mass, frame size, or body composition. For most people, it provides a reasonable target range (±10%), but athletic individuals or those with large/small frames may fall outside this range while still being healthy.

Men and women have different body compositions at the same height. Men typically have higher muscle mass and bone density, while women have higher essential fat percentages. The Hamwi formula accounts for this by using different base weights (48 kg for men vs. 45.5 kg for women) and different increments per inch (2.7 kg for men vs. 2.2 kg for women). This results in men having higher ideal weights than women at the same height, reflecting natural physiological differences.

The Hamwi formula uses 5 feet (152 cm) as the baseline. For heights under 5 feet, use the base weight directly: 48 kg (106 lbs) for men and 45.5 kg (100 lbs) for women. However, for very short heights, other formulas or BMI-based calculations may be more appropriate. Consult with a healthcare provider for personalized assessment, especially for heights below 4'10" (147 cm).

Yes, the Hamwi formula provides a reasonable target for weight loss goals. However, don't fixate on the exact number - use the ±10% range to account for individual differences. If you're significantly above your ideal weight, aim for gradual loss (0.5-1 kg or 1-2 lbs per week). Focus on sustainable lifestyle changes rather than rapid weight loss. Consider body composition (muscle vs. fat) alongside weight. Consult healthcare providers or dietitians for personalized weight loss plans, especially if you have medical conditions.

The Hamwi formula may underestimate ideal weight for muscular or athletic individuals since it doesn't account for muscle mass. Bodybuilders, athletes, and those who strength train regularly often weigh more than the formula suggests while maintaining low body fat. For athletic populations, consider: 1) Body composition analysis (DEXA, bioimpedance), 2) Body fat percentage targets (10-20% for men, 18-28% for women), 3) Performance metrics rather than weight alone, 4) Waist-to-height ratio for health assessment. Your "ideal" weight may be 10-20% above Hamwi's estimate if you have significant muscle mass.

Frame size (skeletal structure) can affect ideal weight by 5-10%. Measure your wrist circumference or elbow breadth to estimate frame: Small frame: Aim for lower end of ±10% range. Medium frame: Use the calculated ideal weight. Large frame: Target upper end of ±10% range. Wrist measurement (right wrist for right-handed, left for left-handed): Men - Small: <6.5", Medium: 6.5-7.5", Large: >7.5". Women - Small: <5.5", Medium: 5.5-6.25", Large: >6.25". The ±10% range in Hamwi formula partially accounts for frame differences.

💡 Achieving & Maintaining Ideal Weight

🥗 Nutrition Strategies
  • Calculate calorie needs based on ideal weight
  • Eat balanced macros (40% carbs, 30% protein, 30% fat)
  • Focus on whole, unprocessed foods
  • Eat adequate protein (1.6-2.2g per kg ideal weight)
  • Stay hydrated (30-35ml per kg ideal weight)
  • Practice portion control
  • Meal prep for consistency
  • Track intake initially to build awareness
🏃 Exercise & Lifestyle
  • Combine cardio and strength training
  • Aim for 150+ minutes moderate activity weekly
  • Build muscle to increase metabolic rate
  • Stay active throughout the day (NEAT)
  • Get 7-9 hours quality sleep
  • Manage stress (cortisol affects weight)
  • Track progress beyond scale (measurements, photos)
  • Be patient - aim for 0.5-1 kg loss per week
⚕️ Medical Disclaimer

This calculator provides ideal body weight estimates using the Hamwi formula for informational and educational purposes only. It does not replace professional medical advice, diagnosis, or treatment. Ideal weight varies based on many individual factors not captured by this formula. Always consult with your healthcare provider, registered dietitian, or qualified medical professional for personalized weight management guidance, especially if you have medical conditions, are pregnant/nursing, or taking medications. Never make significant dietary or lifestyle changes without medical supervision.