Ideal Weight, BMI, and Body Fat Percentage Calculator – Online, Fast, and Free

What is Ideal Weight?

Ideal weight is an estimate of the body weight considered healthy and appropriate for an individual, primarily based on height and sex. Over time, specialists have developed various formulas to estimate this value, grounded in population data and medical studies.

What is the purpose of calculating Ideal Weight?

Ideal weight calculation serves as a reference to assess whether a person’s weight falls within a healthy range, helping prevent conditions associated with excess or insufficient weight, such as obesity, diabetes, and hypertension.

How does the calculation work?

The calculation is based on the person’s height, converted into extra inches above 152.4 cm (equivalent to 5 feet). From this measurement, a specific multiplier is applied according to the chosen formula and the person’s sex.

Additionally, a healthy weight range based on Body Mass Index (BMI) is also considered, which defines an ideal weight range for each height.

Formulas used

1. Devine Formula

Developed in 1974, the Devine formula is widely used in clinical practice to determine medication dosages based on ideal body weight.

Male: \( 50 + 2.3 \times (\text{polegadas acima de 5 pés}) \) kg
Female: \( 45.5 + 2.3 \times (\text{polegadas acima de 5 pés}) \) kg

2. Hamwi Formula

Developed in 1964, it was widely used to define ideal weight in diets and weight-loss programs.

Male: \( 48.0 + 2.7 \times (\text{polegadas acima de 5 pés}) \) kg
Female: \( 45.5 + 2.2 \times (\text{polegadas acima de 5 pés}) \) kg

3. Robinson Formula

Proposed in 1983, it offers a more realistic approximation of ideal weight by slightly adjusting the multipliers.

Male: \( 52.0 + 1.9 \times (\text{polegadas acima de 5 pés}) \) kg
Female: \( 49.0 + 1.7 \times (\text{polegadas acima de 5 pés}) \) kg

4. Miller Formula

Published in 1983, the Miller formula is more conservative, proposing a smaller weight gain per additional inch.

Male: \( 56.2 + 1.41 \times (\text{polegadas acima de 5 pés}) \) kg
Female: \( 53.1 + 1.36 \times (\text{polegadas acima de 5 pés}) \) kg

5. Healthy weight based on BMI

Body Mass Index (BMI) defines a healthy weight range corresponding to values between 18.5 and 24.9 kg/m². Thus, minimum and maximum ideal weights can be estimated using the formula:

Minimum weight: \( 18.5 \times (\text{altura em metros})^2 \) kg
Maximum weight: \( 24.9 \times (\text{altura em metros})^2 \) kg

Did you know?

• None of these formulas account for factors such as body composition, physical activity level, or bone structure.
• Ideal weight serves as a guideline—not an absolute standard—as each individual has unique characteristics.
• Athletes and highly muscular individuals may have elevated BMIs yet remain healthy.
• This calculation serves more as a public health reference than a clinical rule.

Important

Before starting any weight-loss or weight-gain program, consult a healthcare professional for guidance tailored to your individual needs.

What is Body Fat Percentage?

Body fat percentage represents the proportion of a person’s total weight composed of fat tissue. This value is one of the key indicators of health and physical fitness.

What is the purpose of calculating Body Fat Percentage?

It helps assess the amount of fat accumulated in the body, supporting the development of training, nutrition, and health-monitoring strategies.

How does the calculation work?

The calculation is based on the U.S. Navy formula (US Navy Method), which estimates body fat percentage using simple anthropometric measurements.

Formulas

For Men

$$ 86.010 \times \log_{10}(\text{cintura} - \text{pescoço}) $$

$$ - 70.041 \times \log_{10}(\text{altura}) + 36.76 $$

For Women

$$ 163.205 \times \log_{10}(\text{cintura} + \text{quadril} - \text{pescoço}) $$

$$ - 97.684 \times \log_{10}(\text{altura}) - 78.387 $$

These formulas use base-10 logarithms to adjust body proportions and were developed based on large population samples.

How to take the measurements

• Height: in centimeters, measured barefoot.
• Waist: the narrowest circumference between the thorax and navel.
• Neck: just below the Adam’s apple.
• Hip: the largest circumference around the buttocks (women only).

Interpreting the Results

Results vary depending on age, sex, and physical activity level.

General Classification for Men

• Athlete: 6% to 13%
• Good: 14% to 17%
• Acceptable: 18% to 24%
• Obesity: above 25%

General Classification for Women

• Athlete: 14% to 20%
• Good: 21% to 24%
• Acceptable: 25% to 31%
• Obesity: above 32%

Did you know?

• This method is practical and non-invasive, but may yield inaccuracies if measurements are taken incorrectly.
• More accurate methods such as DEXA or hydrostatic weighing exist, but are less accessible.
• Ideal body fat percentage varies with age, sex, and personal goals.

Important

This calculation provides an estimate. For a more precise and personalized assessment, consult a healthcare professional or certified fitness trainer.