Ideal Body Weight and Healthy Range Estimator

Ideal body weight (IBW) formulas are mathematical equations that estimate a target weight range based primarily on height and sex. These formulas were originally developed for medical purposes, such as calculating medication dosages or assessing nutritional needs in clinical settings. While the term "ideal" can be misleading—these formulas don't define what weight is ideal for you personally—they provide rough estimates based on population averages that can help you understand typical weight ranges for your height. Combined with BMI-based healthy weight ranges, these estimates offer multiple perspectives on weight status.

Whether you're a student learning about health metrics, a professional evaluating weight status, a researcher studying population health, a taxpayer understanding healthcare costs, or a common person interested in understanding weight ranges, ideal body weight formulas provide valuable insights. Different formulas (Devine, Hamwi, Robinson, Miller) use slightly different calculations, which is why they produce different estimates. There is no single "correct" formula—they are all rough approximations based on statistical data from specific populations. Understanding these formulas helps you see weight from multiple perspectives, not just a single number.

Our Ideal Body Weight and Healthy Range Estimator helps you estimate ideal body weight using multiple common formulas and a BMI-based healthy weight range. Simply enter your height, sex, and optionally your current weight, and the calculator automatically computes ideal body weight using four formulas (Devine, Hamwi, Robinson, Miller), shows the average of all formulas, and displays a BMI-based healthy weight range (BMI 18.5-24.9). The calculator works with both metric and US units, and optionally compares your current weight to the estimates.

This tool is perfect for anyone who wants to understand weight ranges, see multiple perspectives on ideal weight, evaluate weight status, and make informed decisions about health. By calculating ideal body weight using multiple formulas and comparing to BMI ranges, you can see weight from different angles. Remember, these are educational estimates based on population averages—always consult healthcare professionals for personalized health assessment and guidance, especially if you have health concerns, are pregnant, breastfeeding, or have a history of disordered eating. This calculator is for educational purposes only and does not provide medical advice or target weight prescriptions.

Ideal Body Weight (IBW) formulas estimate a target weight based primarily on height and sex. These formulas use mathematical equations that add a base weight to a multiplier for each inch over 5 feet. Different formulas use different base weights and multipliers, which is why they produce different estimates. There is no single "correct" formula—they are all rough approximations.

Common Ideal Body Weight Formulas

BMI-Based Healthy Weight Range

In addition to ideal body weight formulas, the calculator shows a BMI-based healthy weight range. This range corresponds to BMI 18.5-24.9 (normal weight category):

• Minimum Healthy Weight: Weight at BMI 18.5 for your height
• Maximum Healthy Weight: Weight at BMI 24.9 for your height
• Range: The weight range that corresponds to normal BMI category

Example: Height 5'10" (178 cm). Minimum = 18.5 × (1.78)² = 58.7 kg (129 lbs). Maximum = 24.9 × (1.78)² = 78.9 kg (174 lbs). Healthy range: 58.7-78.9 kg (129-174 lbs).

Why Multiple Formulas?

Different formulas produce different estimates because they use different base weights and multipliers. For example, for a 5'10" man: Devine = 73 kg, Hamwi = 75 kg, Robinson = 71 kg, Miller = 73 kg. The variation between formulas illustrates that these are estimates, not exact measurements. The calculator shows all formulas plus the average, giving you multiple perspectives on ideal weight rather than a single number.

Step 1: Select Measurement System
Choose between metric (centimeters and kilograms) or US units (feet/inches and pounds). The calculator works with both systems and automatically converts between them. Select the system you're most comfortable with or that matches your measuring tools.

Step 2: Enter Your Height
For metric: Enter your height in centimeters (e.g., 175 cm). For US units: Enter your height in feet and inches (e.g., 5 feet 9 inches). Be as accurate as possible—measure your height without shoes, standing straight against a wall. Accurate height is crucial for accurate ideal weight calculations.

Step 3: Select Sex at Birth
Select your sex at birth (male or female). Ideal weight formulas differ for men and women because men typically have higher muscle mass and larger body size. Accurate sex information ensures accurate calculations. The calculator uses different base weights and multipliers for men vs. women.

Step 4: Enter Your Age (Optional)
Enter your age in years. While ideal weight formulas don't directly use age, the calculator uses it for context and warnings. These formulas are primarily designed for adults (18+), and results may be less accurate for children, adolescents, or older adults (80+).

Step 5: Enter Current Weight (Optional)
If you want to compare your current weight to the estimates, enter your current weight. For metric: Enter weight in kilograms (e.g., 70 kg). For US units: Enter weight in pounds (e.g., 154 lbs). The calculator compares your current weight to ideal weight estimates and BMI healthy range.

Step 6: Calculate Ideal Weight
Click the "Calculate Ideal Weight" button. The calculator: (1) Computes ideal body weight using four formulas (Devine, Hamwi, Robinson, Miller). (2) Calculates the average of all formulas. (3) Computes BMI-based healthy weight range (BMI 18.5-24.9). (4) Optionally compares your current weight to estimates. (5) Displays results with visual charts.

Step 7: Interpret Results in Context
Review the results: ideal weight estimates from each formula, average ideal weight, and BMI healthy range. Remember that these are population-based estimates, not personalized targets. Consider results alongside other factors: body composition, muscle mass, medical history, activity level, and overall health. If you have concerns, discuss results with a healthcare professional for personalized interpretation.

This calculator uses mathematical formulas to compute ideal body weight and BMI-based healthy ranges. Here's how it works:

Devine Formula (1974)

Commonly used in medical settings, especially for medication dosing:

Example: 5'10" (70 inches) man. IBW = 50 + 2.3 × (70 - 60) = 50 + 23 = 73 kg (161 lbs).

Hamwi Formula (1964)

One of the most widely recognized IBW formulas:

Example: 5'10" (70 inches) man. IBW = 48 + 2.7 × (70 - 60) = 48 + 27 = 75 kg (165 lbs).

Robinson Formula (1983)

An alternative calculation method:

Example: 5'10" (70 inches) man. IBW = 52 + 1.9 × (70 - 60) = 52 + 19 = 71 kg (157 lbs).

Miller Formula (1983)

Another common formula used in clinical practice:

Example: 5'10" (70 inches) man. IBW = 56.2 + 1.41 × (70 - 60) = 56.2 + 14.1 = 70.3 kg (155 lbs).

Average of All Formulas

The calculator computes the average of all four formulas:

Example: 5'10" man. Devine = 73 kg, Hamwi = 75 kg, Robinson = 71 kg, Miller = 70.3 kg. Average = (73 + 75 + 71 + 70.3) ÷ 4 = 72.3 kg (159 lbs).

BMI-Based Healthy Weight Range

The calculator also computes a BMI-based healthy weight range:

Example: Height 1.78 m (5'10"). Minimum = 18.5 × 3.1684 = 58.7 kg (129 lbs). Maximum = 24.9 × 3.1684 = 78.9 kg (174 lbs). Range: 58.7-78.9 kg (129-174 lbs).

Complete Worked Example

Setup: 5'6" (168 cm) woman, age 30, current weight 70 kg.

Ideal Weight Calculations:

• Height = 66 inches (5'6")
• Inches over 5 feet = 66 - 60 = 6 inches
• Devine: 45.5 + 2.3 × 6 = 59.3 kg (131 lbs)
• Hamwi: 45.5 + 2.2 × 6 = 58.7 kg (129 lbs)
• Robinson: 49 + 1.7 × 6 = 59.2 kg (130 lbs)
• Miller: 53.1 + 1.36 × 6 = 61.3 kg (135 lbs)
• Average: (59.3 + 58.7 + 59.2 + 61.3) ÷ 4 = 59.6 kg (131 lbs)

BMI Healthy Range:

• Height = 1.68 m
• Minimum = 18.5 × 2.8224 = 52.2 kg (115 lbs)
• Maximum = 24.9 × 2.8224 = 70.3 kg (155 lbs)
• Range: 52.2-70.3 kg (115-155 lbs)

Comparison: Current weight 70 kg is at the upper end of BMI healthy range (70.3 kg max) and above all ideal weight estimates (59.6 kg average). This suggests the person may be slightly above ideal weight estimates, but still within the BMI healthy range.

Here are detailed scenarios showing how different people might use this ideal weight calculator to understand weight ranges:

While ideal weight varies by individual, here are general benchmarks to help you understand typical ideal weight ranges for different heights:

Key Insight: Ideal weight increases with height, and men typically have higher ideal weights than women due to generally higher muscle mass and larger body size. The BMI healthy range is wider than ideal weight estimates, providing a broader perspective on healthy weight. Ideal weight estimates typically fall within the BMI healthy range, but the BMI range allows for more variation. The calculator shows both perspectives to help you understand weight from multiple angles.

This calculator uses simplified assumptions to estimate ideal body weight using population-based formulas. It does not account for many real-world complexities:

Important Note: This calculator is for educational purposes only and does not provide medical advice or target weight prescriptions. Ideal body weight formulas and BMI ranges are rough estimates based on population averages and may not match your individual needs. Real health outcomes involve many factors this tool doesn't model, including body composition, bone density, frame size, age, genetics, medical conditions, and ethnicity. Health is influenced by many factors beyond weight and height, including physical activity, nutrition quality, sleep, stress management, mental health, and medical history. Always consult qualified healthcare professionals for personalized health assessment, interpretation of ideal weight results, and guidance on health-related decisions, especially if you have health concerns, are pregnant, breastfeeding, or have a history of disordered eating.

The information in this calculator is based on established medical research and guidelines from authoritative health organizations. For more detailed information about ideal body weight and healthy weight ranges, please refer to these trusted sources:

• Centers for Disease Control and Prevention (CDC): Healthy Weight – Guidance on healthy weight, BMI, and weight management.
• National Institutes of Health (NIH): BMI Calculator – Information on BMI and healthy weight assessment.
• World Health Organization (WHO): Obesity and Overweight Fact Sheet – International standards for BMI classification and healthy weight ranges.
• Mayo Clinic: Healthy Lifestyle – Medical reference for weight management and healthy living.

Note: This calculator uses established formulas including the Devine formula, Robinson formula, Miller formula, and Hamwi formula, which have been used in clinical settings for ideal body weight estimation.