Weight Calculator

How Much Should I Weigh?

Most people have tried to lose or manage weight at some point, often influenced by media portrayals of the “ideal” body. However, the concept of Ideal Body Weight (IBW) was originally developed for medical purposes—mainly to determine accurate drug dosages—not based on physical appearance. While it has been adapted for use in sports and general health assessments, IBW doesn’t consider muscle mass, fat distribution, or body composition.

It’s important to understand that IBW is only a guideline. Being above or below your ideal weight doesn’t automatically mean you’re unhealthy. Factors like diet, exercise, sleep, and stress play a much bigger role in determining overall wellness than a number on the scale.

Factors That Affect Ideal Weight

1. Age

After puberty, most people stop growing in height. However, with age, we naturally lose lean muscle and may gain body fat. Healthy habits like regular exercise and a balanced diet can help maintain body composition over time.

2. Gender

Men generally weigh more than women due to having greater muscle mass and bone density, even though women naturally carry a higher percentage of body fat.

3. Height

Taller individuals typically weigh more due to a larger body frame and more tissue mass.

4. Body Frame Size

Body frame size (small, medium, or large) affects ideal weight. For example, someone with a larger bone structure will naturally weigh more than someone of the same height with a smaller frame.

Frame Size by Wrist Measurement:

For Women:

• Under 5’2″:

  • Small: < 5.5″

  • Medium: 5.5″–5.75″

  • Large: > 5.75″

• 5’2″ to 5’5″:

  • Small: < 6″

  • Medium: 6″–6.25″

  • Large: > 6.25″

• Over 5’5″:

  • Small: < 6.25″

  • Medium: 6.25″–6.5″

  • Large: > 6.5″

For Men (over 5’5″):

• Small: 5.5″–6.5″

• Medium: 6.5″–7.5″

• Large: > 7.5″

Common IBW Formulas

All formulas are based on height over 5 feet, with a base weight and additional weight per inch.

1. Hamwi Formula (1964)

• Male: 48 kg + 2.7 kg/inch over 5′

• Female: 45.5 kg + 2.2 kg/inch over 5′

2. Devine Formula (1974)

• Male: 50 kg + 2.3 kg/inch over 5′

• Female: 45.5 kg + 2.3 kg/inch over 5′

3. Robinson Formula (1983)

• Male: 52 kg + 1.9 kg/inch over 5′

• Female: 49 kg + 1.7 kg/inch over 5′

4. Miller Formula (1983)

• Male: 56.2 kg + 1.41 kg/inch over 5′

• Female: 53.1 kg + 1.36 kg/inch over 5′

Healthy BMI Range

The World Health Organization (WHO) defines a healthy BMI range as 18.5 to 25 for adults of all genders. BMI is often used in conjunction with IBW to estimate healthy weight. However, it does not differentiate between fat and muscle, and may misclassify athletes or people with muscular builds.

IBW for Children and Teens

For individuals under 18, ideal weight is better assessed using CDC BMI percentile charts based on age and gender:

• Boys (2–20 years): BMI should be between the 5th and 85th percentile

• Girls (2–20 years): BMI should be between the 5th and 85th percentile

Limitations of IBW Calculators

While IBW formulas are helpful for general guidance, they do not account for:

• Body fat vs. muscle ratio

• Activity level

• Genetics

• Health conditions

• Physical disabilities

These calculators are best used as general references, not absolute health standards.

Related Calculator:
BMR & Calorie Calculator, Body Fat Calculator, BMI Calculator

External Resources:
Ideal Weight Calculator on Calculator.net