Understanding Ideal Weight
Ideal body weight (IBW) is a clinical estimate of what a person should weigh based on height and gender. These formulas were originally developed for medical purposes, such as calculating drug dosages, but have become widely used as general health references.
Why Ideal Weight Matters
Knowing your ideal weight range can help with:
- Health Goal Setting: Establishing realistic weight targets for weight loss or gain programs
- Medical Calculations: Healthcare providers use IBW for medication dosing and treatment planning
- Fitness Planning: Understanding your target weight helps design appropriate exercise programs
- Self-Awareness: Having a reference point for evaluating your current weight status
Limitations of Ideal Weight Formulas
While ideal weight calculations are useful, they have important limitations:
- They do not account for muscle mass (athletes may have higher healthy weights)
- They do not consider age-related body composition changes
- Individual variation in bone density and body structure affects results
- Ethnicity can influence optimal body weight ranges
Important Note: Ideal weight formulas provide general estimates only. For personalized health advice, consult with a healthcare professional who can consider your complete health picture.
Ideal Weight Formulas Explained
Our calculator uses four established formulas to calculate ideal body weight. Each formula was developed through different research and may be more accurate for certain populations.
Devine Formula (1974)
Developed by Dr. B.J. Devine for medication dosing, this is the most widely used formula in clinical settings.
Men: IBW = 50 kg + 2.3 kg × (height in inches − 60)Women: IBW = 45.5 kg + 2.3 kg × (height in inches − 60)Robinson Formula (1983)
A modification of the Devine formula, considered by some to be more accurate for typical populations.
Men: IBW = 52 kg + 1.9 kg × (height in inches − 60)Women: IBW = 49 kg + 1.7 kg × (height in inches − 60)Miller Formula (1983)
Another modification that tends to produce higher ideal weight estimates, especially for taller individuals.
Men: IBW = 56.2 kg + 1.41 kg × (height in inches − 60)Women: IBW = 53.1 kg + 1.36 kg × (height in inches − 60)Hamwi Formula (1964)
The oldest of the commonly used formulas, developed by Dr. G.J. Hamwi for clinical nutrition assessment.
Men: IBW = 48 kg + 2.7 kg × (height in inches − 60)Women: IBW = 45.5 kg + 2.2 kg × (height in inches − 60)Tip: Since formulas can vary significantly, we recommend using the average of all four formulas as your target reference point. This provides a balanced estimate that accounts for the variations between methods.
How Frame Size Affects Ideal Weight
Body frame size accounts for differences in bone structure and overall body build. People with larger frames naturally carry more weight due to larger bones and broader shoulders.
Determining Your Frame Size
The easiest method to determine frame size is the wrist measurement test:
Thumb and middle finger overlap when wrapped around wrist
Thumb and middle finger just touch
Thumb and middle finger do not touch
Wrist Circumference Guidelines
| Height | Small Frame | Medium Frame | Large Frame |
|---|---|---|---|
| Women | |||
| Under 5'2" | < 5.5" | 5.5" - 5.75" | > 5.75" |
| 5'2" - 5'5" | < 6" | 6" - 6.25" | > 6.25" |
| Over 5'5" | < 6.25" | 6.25" - 6.5" | > 6.5" |
| Men | |||
| Over 5'5" | < 6.5" | 6.5" - 7.5" | > 7.5" |
Healthy Weight Range
In addition to ideal weight formulas, our calculator shows your healthy weight range based on Body Mass Index (BMI). A healthy BMI is generally considered to be between 18.5 and 24.9.
BMI Categories
BMI vs. Ideal Weight Formulas
Both BMI and ideal weight formulas have their uses:
- BMI: Provides a range of healthy weights based on height, useful for general population health assessment
- Ideal Weight Formulas: Provide specific target weights based on height and gender, useful for goal setting
- Combined Approach: Using both gives a comprehensive view of your healthy weight options
Note: Neither BMI nor ideal weight formulas account for body composition. Athletes with high muscle mass may fall outside "normal" ranges while being perfectly healthy.
How We Calculate Ideal Weight
Our calculator implements four established formulas and adjusts results based on your inputs. Here is our calculation methodology:
1. Height Conversion
All heights are converted to inches for consistent formula application:
Imperial: Total inches = (feet × 12) + inchesMetric: Total inches = centimeters ÷ 2.542. Formula Application
Each formula calculates inches over 5 feet and applies the appropriate multiplier based on gender.
3. Frame Size Adjustment
Results are adjusted based on body frame:
Small Frame: Result × 0.90 (-10%)Medium Frame: Result × 1.00 (no change)Large Frame: Result × 1.10 (+10%)4. Healthy Range Calculation
We calculate the healthy BMI weight range using:
Minimum healthy weight = 18.5 × height(m)²Maximum healthy weight = 24.9 × height(m)²5. Unit Conversion
Final results are displayed in your selected unit system:
Imperial (lbs) = Metric (kg) × 2.20462