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

What is Ideal Weight?

Ideal weight is an estimate of body weight considered healthy and appropriate for a person, mainly taking into account their height and sex. Different formulas have been developed by experts over time to estimate this value, based on population data and medical studies.

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What is the Ideal Weight calculation for?

The ideal weight calculation serves as a reference to assess if a person's weight is within a healthy range, and can help prevent diseases associated with excess or lack of weight, such as obesity, diabetes, hypertension, among others.

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How does the calculation work?

The calculation is based on the person's height, converted to 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, the calculation of healthy weight according to the Body Mass Index (BMI) is also considered, which defines an ideal weight range for each height.

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Formulas used

1. Devine's Formula

Created in 1974, Devine's formula is widely used in the medical field to determine medication doses based on ideal 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's 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's Formula

Proposed in 1983, it seeks a more realistic approximation for ideal weight, 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's Formula

Published in 1983, Miller's formula is more conservative, proposing less 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 according to BMI

The Body Mass Index (BMI) considers a healthy weight range corresponding to values between 18.5 and 24.9 kg/m². Thus, we can estimate the minimum and maximum ideal weight with the formula:

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

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Fun Facts

• None of these formulas consider factors such as body composition, physical activity level, or bone structure.
• Ideal weight serves as a guide, not as an absolute standard. Each person has unique characteristics.
• Athletes and very muscular people may have a high BMI, yet still be healthy.
• The calculation is more of a public health reference than a medical rule.

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Important

Before starting any weight loss or gain program, consult a health professional for guidance appropriate to your individual needs.

What is Body Fat Percentage?

Body fat percentage represents the proportion of a person's weight that is composed of fat. This value is one of the main indicators of health and physical fitness, being more specific than BMI, as it considers body composition.

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What is the Body Fat Percentage calculation for?

It serves to assess the amount of fat accumulated in the body, assisting in defining training strategies, diet, and health monitoring. It is useful for athletes, health professionals, and anyone interested in tracking their body composition.

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How does the calculation work?

The calculation used is based on the United States Navy formula (US Navy Method), which estimates body fat percentage through simple measurements: height, waist and neck circumference for men, and waist, neck, and hip circumference for women.

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Formulas

For Men

$$ \text{Percentual de Gordura} = 86.010 \times \log_{10}(\text{cintura} - \text{pescoço}) $$

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

For Women

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

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

These formulas use the base-10 logarithm to adjust body proportions and were developed from studies with large populations.

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How to take measurements

• Height: in centimeters, measured without shoes.
• Waist: the smallest circumference between the chest and the navel.
• Neck: just below the Adam's apple.
• Hip: the largest circumference of the gluteal region (only for women).

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Interpretation of Results

Results vary according to age, sex, and physical activity level. In general, lower percentages indicate less body fat accumulation, while higher values may indicate overweight or obesity.

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General Classification for Men

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

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General Classification for Women

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

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Fun Facts

• This method is practical and non-invasive, but may have small inaccuracies if measurements are taken incorrectly.
• There are more accurate methods, such as DEXA (dual-energy X-ray absorptiometry) or hydrostatic weighing, but they are more expensive and less accessible.
• The ideal body fat percentage varies with age, sex, and personal goal (aesthetics, health, sports performance).

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Important

This calculation provides an estimate. For a more accurate assessment suited to your needs, seek a health professional or a physical educator.