How to calculate your BMI?
Calculating your BMI is quick and easy:
- Enter your height in centimeters (cm) or feet/inches.
- Enter your weight in kilograms (kg) or pounds (lbs).
- Your BMI is calculated instantly and displayed with your weight category.
Understanding your BMI result
BMI categories help you understand where you stand:
- Underweight: BMI below 18.5 — You may need to gain weight.
- Normal weight: BMI 18.5–24.9 — This is the healthy range.
- Overweight: BMI 25–29.9 — Consider lifestyle changes.
- Obese: BMI 30 or above — Consult a healthcare professional.
What does BMI measure?
BMI is a simple calculation using your height and weight that provides a reliable indicator of body fatness for most people. It's used worldwide as a screening tool to identify potential weight-related health risks.
What is BMI and why does it matter?
Body Mass Index (BMI) is a numerical value derived from your weight and height. The formula is simple: weight in kilograms divided by height in meters squared (kg/m²). Developed by Belgian mathematician Adolphe Quetelet in the 1830s, BMI has become one of the most widely used screening tools for categorizing weight status across populations. While it doesn't directly measure body fat, numerous studies have shown strong correlations between BMI and more direct measures of adiposity. A normal BMI (18.5–24.9) is associated with the lowest risk of weight-related health problems including heart disease, type 2 diabetes, certain cancers, and premature death. Being significantly underweight or overweight can increase these risks substantially.
Limitations of BMI
While BMI is a useful screening tool, it has important limitations. It doesn't distinguish between muscle mass and fat mass — athletes and bodybuilders may have a high BMI despite having low body fat. Age and sex also play roles; older adults tend to have more body fat than younger adults at the same BMI, and women typically have more body fat than men at the same BMI. Ethnicity matters too — some populations (such as South Asians) may face health risks at lower BMI thresholds. Additionally, BMI doesn't account for fat distribution, which is crucial since abdominal fat carries higher health risks than fat stored elsewhere. For these reasons, BMI should be used as one piece of information alongside other assessments like waist circumference, body composition analysis, and overall health indicators.
Healthy weight ranges
For a given height, the healthy BMI range corresponds to a specific weight range. Here are some examples: At 160 cm (5'3"), a healthy weight is approximately 47.5–63.8 kg (105–141 lbs). At 170 cm (5'7"), it's about 53.5–71.7 kg (118–158 lbs). At 180 cm (5'11"), the range is roughly 60.1–80.4 kg (132–177 lbs). Our calculator shows your personal healthy weight range based on your exact height. Remember that these are general guidelines — individual optimal weight can vary based on body composition, muscle mass, bone density, and other factors.
Frequently Asked Questions (FAQs)
What is a healthy BMI range?
A healthy BMI range is 18.5 to 24.9. Below 18.5 is considered underweight, 25 to 29.9 is overweight, and 30 or above is obese. These categories are established by the World Health Organization (WHO) and are based on extensive research linking BMI to health outcomes.
Is BMI accurate for everyone?
BMI is a useful screening tool for most adults, but it has limitations. It doesn't distinguish between muscle and fat, so athletes with high muscle mass may have a high BMI without excess body fat. It also doesn't account for fat distribution, age, sex, or ethnicity differences. For a complete health assessment, combine BMI with other measures like waist circumference, blood pressure, cholesterol levels, and diet quality.
How is BMI calculated?
BMI is calculated by dividing your weight in kilograms by your height in meters squared. The formula is: BMI = weight (kg) ÷ [height (m)]². For example, if you weigh 70 kg and are 1.75 m tall: BMI = 70 ÷ (1.75 × 1.75) = 22.9, which falls in the normal weight range.
Does BMI work for children and teenagers?
BMI interpretation for children and teenagers (ages 2–19) is different from adults. For this age group, BMI is plotted on growth charts and expressed as a percentile relative to other children of the same age and sex. A pediatric BMI calculator should be used instead of the adult calculator on this page.
Can I trust my BMI result?
Our calculator uses the standard WHO formula and provides accurate mathematical results. However, remember that BMI is just one indicator of health. For personalized health advice, especially if your BMI indicates underweight or obesity, consult a healthcare professional who can consider your full medical history, body composition, and lifestyle factors.
What is my healthy weight for my height?
Using the healthy BMI range of 18.5–24.9, our calculator computes your ideal weight range based on your height. For example, at 170 cm tall, a healthy weight would be approximately 53.5–71.7 kg. This gives you a target range to aim for if weight management is part of your health goals.
