âš¡ BMI Calculator

Calculate your Body Mass Index and see your health category instantly.

About This Tool

BMI Calculator

Calculate your Body Mass Index (BMI) instantly and understand your weight category — Underweight, Normal, Overweight, or Obese.

Why Use This Tool?

  • Track your fitness progress over time with consistent BMI monitoring
  • Doctors and health professionals use BMI as a screening tool
  • Understand your healthy weight range for your height
  • Used for insurance forms, medical checkups, and fitness assessments
  • Calculate BMI for both metric (kg/cm) and imperial (lbs/inches) units

Overview

Body Mass Index, or BMI, is a simple numerical measure calculated from a person's height and weight. It is widely used by healthcare professionals as a quick screening tool to assess whether an individual is underweight, at a healthy weight, overweight, or obese. Our free BMI Calculator instantly calculates your BMI using both metric (kilograms and centimetres) and imperial (pounds and inches) units, and shows you exactly which WHO-defined weight category you fall into. While BMI is a useful initial screening tool, it is important to understand its limitations — it does not directly measure body fat percentage, and factors like muscle mass, age, gender, and ethnicity can affect interpretation. Athletes, for example, may have a high BMI due to muscle mass rather than excess fat. Despite its limitations, BMI remains one of the most widely used health metrics globally because of its simplicity and consistency. Use our calculator to get your instant BMI score along with a clear explanation of what it means for your health and your ideal weight range.

How to Use

  • 1

    Choose Your Unit System

    Select Metric (kg/cm) or Imperial (lbs/inches) depending on which measurements you have available.

  • 2

    Enter Your Weight

    Type your current weight in kilograms (or pounds for imperial). Be as accurate as possible for the best result.

  • 3

    Enter Your Height

    Enter your height in centimetres (or feet and inches for imperial).

  • 4

    Get Your BMI

    Your BMI score is calculated instantly and displayed with your weight category (Underweight, Normal, Overweight, Obese).

  • 5

    Read Your Healthy Range

    The tool also shows your healthy weight range for your height so you know what to aim for.

Frequently Asked Questions

According to WHO guidelines, a BMI between 18.5 and 24.9 is considered healthy for adults. Below 18.5 is underweight, 25–29.9 is overweight, and 30 or above is obese.
BMI is a general screening tool and may not be accurate for athletes, the elderly, pregnant women, or children. Consult a doctor for a comprehensive health assessment.
No. Children and teenagers use age- and sex-specific BMI percentile charts, not the standard adult BMI categories.
No. BMI is calculated only from height and weight. It is an indirect indicator of body fat. DEXA scans or hydrostatic weighing measure body fat directly.
For general tracking, once a month or whenever your weight changes significantly. More frequent monitoring is useful when actively trying to lose or gain weight.