IDEAL WEIGHT CALCULATOR

The Ideal Weight Calculator helps you determine your ideal body weight (IBW) range based on your height, gender, and age. Calculating IBW has been a goal for health experts for decades, and multiple formulas have been developed over time. Our calculator allows you to compare the results from the most popular formulas side by side, giving you a comprehensive view of your ideal weight range.

How Much Should You Weigh?

Many people wonder about their “ideal” body weight, often influenced by media, social platforms, movies, and magazines. While popular culture emphasizes appearance, the concept of Ideal Body Weight (IBW) was originally created for medical purposes—primarily to estimate correct drug dosages. Research shows that certain medications are metabolized more accurately based on IBW than on total body weight. Today, IBW is also widely used in sports, where athletes are often classified according to their weight.

It’s important to remember that IBW is not a perfect measure. It doesn’t account for body composition, such as the ratio of muscle to fat. This means that highly fit or muscular individuals may appear “overweight” according to IBW formulas, even if they are perfectly healthy.

Determining how much a person should weigh is not an exact science. No single measure—whether IBW, BMI, or others—can definitively define a healthy weight. These tools serve only as references. Maintaining a healthy lifestyle through regular exercise, balanced nutrition, adequate sleep, and stress management is far more important than focusing solely on a specific weight.

Many factors influence ideal weight, including age, gender, height, genetics, and lifestyle. Other considerations, such as fat distribution, health conditions, and family history, may also play a role. Use IBW as a helpful guideline, but remember that individual health and fitness are far more important than hitting an exact number.

Factors Affecting Ideal Body Weight

• Age — After the teenage years—roughly ages 14–15 for girls and 16–17 for boys—age has minimal impact on ideal body weight (IBW) since most people have reached their adult height. However, as we age, it is natural to lose height—approximately 1.5 inches for men and 2 inches for women by age 70. Additionally, lean muscle mass decreases while body fat tends to accumulate more easily. Although aging is inevitable, maintaining a healthy lifestyle through diet, exercise, sleep, and stress management can help reduce these effects.
• Gender — Males and females naturally differ in weight due to variations in body composition. Men typically have higher muscle mass, which is denser than fat, and slightly higher bone density. Women, despite generally having a higher percentage of body fat, usually weigh less than men of the same height. Height differences also contribute, as men tend to be taller on average.
• Height — Height is directly linked to weight since taller individuals naturally carry more muscle and fat. For example, a male and female of the same height may have a 10–20% weight difference due to differences in muscle mass, bone density, and body composition.
• Body Frame Size —Bone structure can significantly affect ideal body weight. Body frame size is usually categorized as small, medium, or large and is often estimated by measuring the circumference of the wrist relative to height. Those with larger frames tend to weigh more, even with similar body composition.

Body Frame Size and Ideal Weight

Body frame size significantly influences ideal body weight, as individuals with larger bone structures naturally weigh more than those with smaller frames, even at the same height. Body frame size is typically determined by measuring wrist circumference and categorizing it as small, medium, or large.

For Women:

• Height under 5’2″:

  • Small frame: wrist < 5.5″

  • Medium frame: wrist 5.5″ – 5.75″

  • Large frame: wrist > 5.75″

• Height 5’2″ – 5’5″:

  • Small frame: wrist < 6″

  • Medium frame: wrist 6″ – 6.25″

  • Large frame: wrist > 6.25″

• Height over 5’5″:

  • Small frame: wrist < 6.25″

  • Medium frame: wrist 6.25″ – 6.5″

  • Large frame: wrist > 6.5″

For Men:

• Height over 5’5″:

  • Small frame: wrist 5.5″ – 6.5″

  • Medium frame: wrist 6.5″ – 7.5″

  • Large frame: wrist > 7.5″

Understanding your body frame size helps provide a more accurate estimate of your ideal body weight (IBW) and offers better context for metrics like BMI.

Formulas for Calculating Ideal Body Weight (IBW)

Ideal Body Weight (IBW) formulas were initially developed to help calculate appropriate drug dosages based on a person’s height. All formulas use a similar structure: a base weight for a height of 5 feet, plus a fixed weight increment for each inch above 5 feet.

Example: For a 5’10” male using the Devine formula:

• Base weight = 50 kg

• Increment = 2.3 kg × 10 inches = 23 kg

• Estimated IBW = 50 + 23 = 73 kg (~161 lbs)

Different formulas use slightly different base weights and increments, based on the research and findings of the scientists who developed them.

1. G. J. Hamwi Formula (1964)

• Male: 48.0 kg + 2.7 kg per inch over 5 feet

• Female: 45.5 kg + 2.2 kg per inch over 5 feet

• Originally designed for medicinal dosage purposes.

2. B. J. Devine Formula (1974)

• Male: 50.0 kg + 2.3 kg per inch over 5 feet

• Female: 45.5 kg + 2.3 kg per inch over 5 feet

• Similar to Hamwi, but it became the most widely used formula for IBW over time.

3. J. D. Robinson Formula (1983)

• Male: 52 kg + 1.9 kg per inch over 5 feet

• Female: 49 kg + 1.7 kg per inch over 5 feet

• A modification of the Devine formula.

4. D. R. Miller Formula (1983)

• Male: 56.2 kg + 1.41 kg per inch over 5 feet

• Female: 53.1 kg + 1.36 kg per inch over 5 feet

• Another adjustment of the Devine formula.

These formulas provide a useful reference for estimating ideal weight, but it’s important to remember that individual differences in muscle mass, body fat, and health conditions may affect your actual healthy weight.

Healthy BMI Range

The World Health Organization (WHO) recommends a healthy Body Mass Index (BMI) range of 18.5–25 for adults, regardless of gender. BMI is a widely used metric to estimate a healthy weight for a given height and serves as a quick indicator of potential health risks.

A higher BMI is generally associated with an increased likelihood of health issues, including obesity, diabetes, cardiovascular disease, and other chronic conditions. Doctors often monitor BMI trends over time to advise patients on potential risks and lifestyle changes.

Healthy BMI for Children and Teens

The adult BMI formulas are not suitable for children and teens under 18. For younger individuals, the Centers for Disease Control and Prevention (CDC) provides BMI percentile charts. Children and adolescents should maintain a BMI between the 5th and 85th percentile for their age:

• CDC BMI chart for boys (ages 2–20)

• CDC BMI chart for girls (ages 2–20)

These percentiles adjust for growth patterns and ensure healthy development.

Limitations of the Ideal Weight Calculator

While our Ideal Weight Calculator provides a useful reference, it has limitations:

• The formulas primarily consider height and gender, without factoring in muscle mass, body fat percentage, activity levels, or body composition.

• It may not be fully accurate for individuals with physical disabilities, extremely high or low body weights, or unusual body proportions.

• Results should be treated as general guidelines, not strict targets.

Remember, ideal weight is individualized, and overall health depends on a combination of balanced nutrition, regular exercise, and lifestyle habits, rather than a single number.