BMI Calculator
Calculate your body mass index using height and weight, then view a simple BMI category for general awareness.
Simple, fast and clear
Enter your values, review the result, and read the formula used so the calculation is easy to understand.
BMI Calculator
Use the fields below to calculate your result instantly.
What is the BMI Calculator?
A BMI calculator estimates body mass index using height and weight. BMI is a simple screening number that helps adults understand whether their weight falls in a broad underweight, normal, overweight or obesity range for their height.
BMI is popular because it is quick and easy to calculate, but it does not directly measure body fat, muscle mass, bone density or overall health. Athletes, pregnant people, older adults and people with high muscle mass may need a more complete assessment.
Use this calculator as a general awareness tool. If the result is outside the expected range or if you have health concerns, review it with a qualified medical professional rather than making decisions from BMI alone.
How we calculate the result
Formula: BMI = weight in kilograms / (height in meters x height in meters)
The calculator converts height from centimeters to meters, then squares the height value. Weight in kilograms is divided by that squared height. For example, if height is 1.70 m and weight is 70 kg, BMI equals 70 / (1.70 x 1.70).
The result is compared with common adult BMI categories. These categories are broad screening ranges and may not apply equally to every person, age group or body type.
When to use this calculator
Use this calculator for general fitness awareness, weight-range discussion and quick health screening before exploring more detailed measurements.
Input tips for better results
Enter weight in kilograms and height in centimeters. If you measured height in feet and inches, convert it first. BMI is sensitive to height, so a small height error can move the result.
Compare BMI with other health signals such as waist measurement, fitness level, body composition and medical history.
Limitations of this calculator
This BMI Calculator is an educational estimate. It cannot replace official records, professional advice, medical advice, accounting documents, tax filings, lender statements or employer payroll records.
Real-world health example
Use BMI Calculator as a screening or planning number, then compare it with other signals such as energy level, body measurements, training history and professional advice. Health calculators are useful for awareness, but they do not understand every body type or medical situation.
Mistakes to avoid
Do not treat one calculator result as a diagnosis. Enter the correct units, avoid rounded guesses where possible and review unusual results with a qualified professional.
Frequently Asked Questions
Is BMI a diagnosis?
No. BMI is a screening estimate and not a medical diagnosis.
Why does height need to be squared?
Squaring height adjusts weight relative to body size, which makes comparison more meaningful than weight alone.
Can BMI be wrong for muscular people?
Yes. High muscle mass can increase BMI even when body fat is not high.
Helpful tips
- Enter weight in kilograms and height in centimeters. If you measured height in feet and inches, convert it first. BMI is sensitive to height, so a small height error can move the result.
- Compare BMI with other health signals such as waist measurement, fitness level, body composition and medical history.
- Do not treat BMI as a diagnosis. It is a quick indicator, not a full health assessment.
- BMI is a screening metric. It does not distinguish muscle, fat, bone density, pregnancy, age-related changes or athletic body composition.
Before you rely on the result
BMI is a screening metric. It does not distinguish muscle, fat, bone density, pregnancy, age-related changes or athletic body composition. Keep the input values with the result so you can review the assumption later.