The ideal weight calculator computes the healthy Ideal Weight (IBW) based on height and gender using the divine formula. IBW provides an indication of the risk of obesity-related diseases or malnutrition and helps determine the weight at which an individual has the lowest risk of health complications based on their height and sex.

IBW is commonly used in medicine for drug dosing, during mechanical ventilation, and for assessing nutritional needs.

For adults, IBW is often calculated using several formulas, the most popular being the Devine formula:

Devine Formula for Women (inches):
Women: 45.5 + 2.3 × (height in inches − 60)
Devine Formula for Women (centimeters):
Women: 45.5 + 0.91 × (height in cm − 152.4)
Devine Formula for Men (inches):
IBW = 50 + 2.3 × (height in inches − 60)
Devine Formula for Men (centimeters):
IBW = 50 + 0.91 × (height in cm − 152.4)

For children, ideal body weight is calculated using different formulas that depend on age, height, and sex.

Our IBW calculator allows you to determine your ideal body weight IBW in (kg) instantly by entering your gender and height in (cm).

To convert units use this table

Height & Weight Conversion for IBW Calculator (US & International Units)

From	To	Conversion
cm	inches	÷ 2.54
cm	feet	÷ 30.48
kg	lb	× 2.205

Note: To convert back, simply reverse the operation (multiply or divide as appropriate

This calculator does not apply to children. For pediatric IBW, you can use specific formulas that are based on age, or the CDC chart for male children, or the CDC ideal body weight chart for female children to estimate your child’s ideal weight based on age, height, and gender.

What Is Ideal Body Weight?

Ideal Body Weight (IBW) is an estimate of a healthy body weight based mainly on a person’s height and sex. It provides a reference weight that is considered appropriate for optimal health and normal body function.

In clinical practice, IBW is commonly used for medication dosing (such as antibiotics and chemotherapy), mechanical ventilation settings, and nutritional assessment.

Unlike BMI, which classifies weight status based on actual body weight, IBW estimates a person’s weight based on height and biological differences between men and women.

Ideal Body Weight for Females

Height (cm)	Height (in)	Devine IBW Range (kg)
150–155	59.1–61.0	45–48
157–162	61.8–63.8	50–54
165–170	65.0–67.0	57–61
172–177	67.7–69.7	62–66
180–185	71.0–73.0	68–72

Ideal Body Weight for Males

Height (cm)	Height (in)	Devine IBW Range (kg)
150–155	59.1–61.0	50–52
157–162	61.8–63.8	54–57
165–170	65.0–67.0	59–62
172–177	67.7–69.7	63–67
180–185	71.0–73.0	69–73

When Do You Need to Use the IBW Calculator?

1. Medication Dosing

Many medications are dosed based on a person’s weight, but using the actual weight can be misleading for underweight or obese patients. Ideal Body Weight (IBW) helps determine the safe and effective dose.

For patients obese patients, doctors often use the Adjusted Body Weight (ABW):

ABW = IBW + 0.4 × (Actual Weight − IBW).

This ensures medication is neither under- nor overdosed. IBW is most commonly used for drugs like antibiotics, chemotherapy, and ventilator settings, giving healthcare providers a reliable reference based on height, sex, and body composition.

2. Mechanical Ventilation

Guides the setting of tidal volumes (breath size) to protect the lungs and prevent ventilator-induced lung injury (VILI).

3. Nutritional Assessment

Provides a baseline for evaluating nutritional status, complementing BMI measurements for a more accurate assessment.

How to Calculate Your IBW and Determine Your Weight Category

Step 1: Determine Your Ideal Body Weight (IBW)

Enter your height and gender into the calculator and press “Calculate”. Your ideal body weight will appear instantly. You can also use the Devine formula manually.

Step 2: Calculate Your Percentage of Ideal Body Weight (%IBW)

%IBW = (Current Weight ÷ Ideal Body Weight) × 100

Step 3: Identify Your Weight Category by %IBW

%IBW	Classification
>120%	Obese
110–120%	Overweight
90–109%	Ideal / Healthy Weight
80–89%	Underweight (mild)
<70%	Severe Underweight

Step 4: Calculate BMI for More Accuracy

BMI = Weight (kg) ÷ [Height (m)]²

Step 5: USE BMI to Identify your Weight Category by Classification (WHO)

BMI (kg/m²)	Classification
<18.5	Underweight
18.5 – 24.9	Healthy Weight
25.0 – 29.9	Overweight
≥30.0	Obesity

Step 6: Calculate Adjusted Body Weight (for Overweight Patients)

If overweight, use your IBW to calculate Adjusted Body Weight (ABW) for medication dosing or ventilation settings.

IBW vs BMI

Feature	Ideal Body Weight (IBW)	Body Mass Index (BMI)
Based on	Height + Sex	Weight + Height
Purpose	Clinical reference weight	Weight status classification
Used for	Ventilation settings, drug dosing	Assessing healthy weight category
Output	Single estimated weight (kg)	Numerical value with category
Result Type	Reference weight	Underweight / Normal / Overweight / Obese

Factors That Affect Ideal Body Weight

Several factors influence your ideal body weight, which is why formulas provide estimates rather than exact numbers:

1. Height: Taller individuals generally have higher ideal weight due to increased bone and muscle mass.

2. Gender: Women generally weigh less than men of the same height due to biological differences in body composition and metabolism. Men typically have more muscle mass and denser bones, so Ideal Body Weight formulas are adjusted based on sex.

3. Body Frame Size: Small, medium, or large-boned frames affect your healthy weight range. Wrist measurements can help estimate frame size.

Gender	Wrist Circumference	Body Frame Size
Female	< 14 cm	Small
Female	14 – 16 cm	Medium
Female	> 16 cm	Large
Male	< 16 cm	Small
Male	16 – 18 cm	Medium
Male	> 18 cm	Large

4. Age:

After full growth, age has minimal effect on Ideal Body Weight. However, muscle loss and fat gain with aging can affect health, as metabolism and body composition change over time. Age remains an important factor for children (still growing) and older adults (over ~70 years), when changes in height, muscle, and fat can influence weight recommendations.

5. Lifestyle & Genetics: Can account for 30–70% of BMI, influencing appetite, metabolism, and fat storage. Activity level, diet, and family history can shift your body composition.

6. Medical Conditions & Medications: Health issues or certain drugs may alter metabolism, appetite, or fat distribution.

IBW Formulas for Adults

Formula	Men (kg)	Women (kg)
Devine	50 + 2.3 × (height in inches − 60)	45.5 + 2.3 × (height in inches − 60)
Broca	height (cm) − 100	(height cm − 100) × 0.9
Lorentz	(height − 100) − ((height − 150)/4)	(height − 100) − ((height − 150)/2)
Miller	56.2 + 1.41 × (height in inches − 60)	53.1 + 1.36 × (height in inches − 60)

Limitations of Ideal Body Weight Formulas

Ignores Body Composition: IBW does not distinguish between fat and muscle. A muscular individual may appear overweight despite having low body fat.
Doesn’t Account for Frame Size: Standard formulas do not fully consider body width, trunk length, or bone structure, which can influence a healthy weight.
Oversimplifies Health: IBW focuses on a single number, overlooking important factors like fat distribution (e.g., visceral fat) and overall health indicators.
Age & Gender Inaccuracies: The formulas may not accurately reflect age-related changes in body fat or variations in body types between genders.
Inaccurate for Extremes: IBW can be unreliable for very short or very tall individuals, or those with physical disabilities.
Medication Dosing Risks: Relying solely on IBW for drug dosing may result in under- or overdosing, especially in pediatric or critically ill patients.

How to calculate ideal body weight for children?

Age Group	IBW Formula
Infant (< 12 months)	IBW (kg) = (Age in months + 9) ÷ 2
Pediatric (1–5 years)	IBW (kg) = 2 × (Age in years + 5)
Children (5–14 years)	IBW (kg) = 4 × Age in years