Calculating body weight often involves using different methods based on what you need the weight for. While a simple scale gives your current weight, ideal body weight (IBW) is often used in medical settings, particularly for medication dosages. This calculation considers your height and sex.
Ideal Body Weight (IBW) Calculation
The following formulas calculate Ideal Body Weight for those taller than 5 feet (60 inches or 152 cm).
Important Note: These formulas are intended as a guideline and may not suit everyone perfectly. Factors like body composition (muscle vs. fat), age, and overall health aren't considered.
| Sex | Formula |
|---|---|
| Male | IBW = 50 kg + 2.3 kg for each inch over 5 feet |
| Female | IBW = 45.5 kg + 2.3 kg for each inch over 5 feet |
How to Use the Formulas:
- Convert Height to Inches: Measure your height in feet and inches. Then convert it all to inches. Remember that 1 foot equals 12 inches. For example, if you are 5 feet 6 inches, you have 66 inches (60+6).
- Calculate Inches Over 5 Feet: Subtract 60 inches (5 feet) from your total height in inches. This value shows you how many inches taller you are than 5 feet. Using our example from before 66 inches - 60 inches = 6 inches.
- Calculate IBW
- For Males: Multiply the number of inches over 5 feet by 2.3 and add 50 kg. Using an example of a man who is 5'6" we would calculate 6 inches * 2.3kg = 13.8 kg. We would then add 50kg + 13.8kg = 63.8kg IBW.
- For Females: Multiply the number of inches over 5 feet by 2.3 and add 45.5 kg. Using an example of a woman who is 5'6" we would calculate 6 inches * 2.3kg = 13.8 kg. We would then add 45.5kg + 13.8kg = 59.3kg IBW.
Example Calculations:
- Male Example: A man who is 5 feet 10 inches tall would calculate as follows. 5 ft * 12 inches/ft = 60 inches + 10 inches = 70 inches. 70 inches - 60 inches = 10 inches. 10 inches * 2.3 kg/inch = 23 kg. 50 kg + 23kg = 73 kg IBW.
- Female Example: A woman who is 5 feet 4 inches tall would calculate as follows: 5 ft * 12 inches/ft = 60 inches + 4 inches = 64 inches. 64 inches - 60 inches = 4 inches. 4 inches * 2.3 kg/inch = 9.2 kg. 45.5 kg + 9.2 kg = 54.7 kg IBW.
Why Use Ideal Body Weight?
- Medication Dosage: In obese patients, medications are sometimes dosed based on IBW or adjusted body weight (ABW), rather than total body weight, to avoid overdosing.
- Medical Guidelines: IBW is used for many calculations such as medical guidelines and can be used to help set health goals.
Important Considerations:
- Limitations: This method for calculating IBW is for people taller than 60 inches (152 cm). It also doesn't account for muscle mass or frame size.
- Professional Advice: Always consult a healthcare professional for personalized weight assessment and guidance.
