BMI Calculator: Get Your Personal Health Number Instantly

Are you trying to determine if your current weight is healthy?

Millions of people follow diets and exercise plans without knowing if they’re actually addressing their specific health needs.

Our BMI Calculator helps solve this problem by providing your body mass index—a key indicator used by doctors to assess weight-related health risks—giving you a clearer picture of where to focus your wellness efforts.

Browsing the maze of online fitness resources, it’s easy to be overwhelmed by complex terms and data points. But in the world of fitness, keeping track of basic metrics can shape your journey to health and wellness. One such vital metric is the Body Mass Index (BMI).

Bridging the simplicity of measurement and complexity of understanding, a BMI calculator is an ideal tool to ascertain your health status.

What Is a BMI Calculator?

BMI Calculator, a handy tool often overlooked, is used to determine your Body Mass Index – an indicator of well-being. It does so by comparing your weight and height input.

How To Use the BMI Calculator?

Using a BMI calculator is clear-cut. By providing your height and weight, the calculator efficiently spews out your current BMI, enabling a snapshot of your bodily health.

These calculators are not age-specific and provide invaluable health insights for adults over the age of 20. It does, however, note that interpretation for those younger differs.

BMI table for adults

This is the World Health Organization’s (WHO) recommended body weight based on BMI values for adults. It is used for both men and women, age 20 or older.

Classification	BMI range – kg/m2
Severe Thinness	< 16
Moderate Thinness	16 – 17
Mild Thinness	17 – 18.5
Normal	18.5 – 25
Overweight	25 – 30
Obese Class I	30 – 35
Obese Class II	35 – 40
Obese Class III	> 40

Interpreting Your BMI Result

Interpreting BMI is a game of categories. Each number range represents a health status, from underweight to obese.

Knowing your BMI score contributes to a complete picture of your health and could influence lifestyle decisions. Remember, it’s not a diagnostic tool, but it does signpost if potential weight-related health issues might be around the corner.

BMI formula

Below are the equations used for calculating BMI in the International System of Units (SI) and the US customary system (USC) using a 5’10”, 160-pound individual as an example:

USC Units:

BMI = 703× mass (lbs)height2 (in)  = 703× 160702  = 23.0

SI, Metric Units:

BMI =  mass (kg)height2 (m)  =  72.571.7782  = 23.0

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Health Risks Linked to Being Overweight

Being overweight significantly raises the risk of developing various serious health conditions and diseases. According to the Centers for Disease Control and Prevention (CDC), these risks include:

• High blood pressure
• Unhealthy cholesterol levels: Elevated LDL (“bad” cholesterol), reduced HDL (“good” cholesterol), and high triglycerides
• Type 2 diabetes
• Coronary heart disease
• Stroke
• Gallbladder disease
• Osteoarthritis: A joint condition caused by the breakdown of cartilage
• Sleep apnea and respiratory issues
• Certain cancers: Including endometrial, breast, colon, kidney, gallbladder, and liver cancer
• Reduced quality of life
• Mental health disorders: Such as clinical depression, anxiety, and others
• Body pain and impaired physical function
• Increased risk of premature death compared to individuals with a healthy BMI

As evident from the list above, being overweight can lead to numerous adverse health outcomes, some of which can be life-threatening. To minimize these risks, it is generally recommended to maintain a BMI below 25 kg/m². However, individuals should consult their healthcare provider to assess whether lifestyle changes are necessary to improve their overall health.

Health Risks Linked to Being Underweight

Being underweight carries its own set of health risks, which can have serious consequences. Below are some of the key risks associated with being underweight:

• Malnutrition, vitamin deficiencies, and anemia: Reduced ability of blood to carry oxygen
• Osteoporosis: A condition that weakens bones, making them more prone to fractures
• Weakened immune function: Increased susceptibility to infections and illnesses
• Growth and developmental issues: Especially in children and teenagers
• Reproductive problems in women: Hormonal imbalances can disrupt menstrual cycles, and underweight women face a higher risk of miscarriage during the first trimester
• Surgical complications: Greater likelihood of issues during or after surgery
• Increased risk of premature death compared to individuals with a healthy BMI

In some cases, being underweight may indicate an underlying health condition, such as anorexia nervosa, which comes with its own set of risks. If you or someone you know is underweight—especially if the cause is unclear—it is important to consult a healthcare professional for evaluation and guidance.

Limitations of BMI

While BMI (Body Mass Index) is a widely used and helpful tool for assessing healthy body weight, it has several limitations. BMI is an estimate and does not account for body composition. Given the diversity in body types, muscle distribution, bone mass, and fat distribution, BMI should be used alongside other measurements rather than as the sole indicator of a person’s healthy weight.

In Adults:

BMI may not always be accurate because it measures excess body weight rather than excess body fat. It is also influenced by factors such as age, sex, ethnicity, muscle mass, body fat percentage, and activity level. For example:

• An older adult classified as a healthy weight but leading a sedentary lifestyle may have excess body fat, which is unhealthy, despite having a normal BMI.
• A younger individual with the same BMI but higher muscle mass may be considered healthy.
• Athletes, particularly bodybuilders, may have a higher BMI due to increased muscle mass, which is denser than fat, even though they are at a healthy weight.

According to the CDC:

• Older adults generally have more body fat than younger adults with the same BMI.
• Women typically have more body fat than men at an equivalent BMI.
• Muscular individuals and athletes may have higher BMIs due to greater muscle mass.

In Children and Adolescents:

The limitations of BMI in adults also apply to children and adolescents. Additionally, factors like height and stage of sexual maturation can influence BMI and body fat levels. BMI is a more reliable indicator of excess body fat in obese children than in overweight children, whose BMI may reflect increased levels of either fat or fat-free mass (e.g., muscle, water, organs). In thin children, differences in BMI may also be due to variations in fat-free mass.

Despite these limitations, BMI is a reasonably accurate indicator of body fat for 90-95% of the population. When used in conjunction with other assessments, it can be a valuable tool in determining an individual’s healthy body weight.

Key Takeaway

In fitness, knowing is half the battle. The other half is about taking action. Understanding the concept of BMI and integrating its use into your routine could be the step-up you need on your fitness path. Let’s keep your health in check with our cutting-edge BMI calculator.