BMI Calculator

The BMI Calculator estimates your Body Mass Index from just your height and weight, then places the result into one of the standard categories: Underweight, Normal, Overweight, or Obese. Two unit tabs keep it simple for everyone — Metric (cm / kg) for most of the world and Imperial (ft / lb) for users who measure in feet, inches, and pounds — and both apply the same core idea: weight divided by height squared, with a 703 conversion factor on the imperial side. Results appear instantly as you type, colour-coded and paired with a badge, alongside a healthy weight range computed for your exact height, spanning the 18.5 to 24.9 BMI band. If your number lands at 22.5 the badge reads Normal; at 31.1 it reads Obese, which makes it easy to see whether you sit inside the healthy range or outside it. The tool is deliberately honest about its limits, noting on the page that BMI is a screening measure and does not directly measure body fat, so muscular athletes can read higher than expected. For a quick health check, a starting point for a weight-loss plan, or a benchmark to discuss with a professional, this free BMI calculator with metric and imperial units gets you there in seconds.

1. 1

   Choose the Metric (cm / kg) tab or the Imperial (ft / lb) tab depending on which units you measure in.

2. 2

   On the metric tab, enter your height in the Height field (centimeters) and your weight in the Weight field (kilograms).

3. 3

   On the imperial tab, fill in Height feet, Height inches, and Weight pounds as three separate fields.

4. 4

   Read the large BMI figure and its coloured category badge — both update the moment you finish typing.

5. 5

   Check the Healthy weight (low) and Healthy weight (high) stats to see the weight range that keeps you inside 18.5–24.9.

• Running a routine weight check before starting a diet plan.
• Tracking BMI change month to month during a weight-loss program.
• Finding the weight range to aim for at a given height.
• Screening whether a client falls inside the normal band in a coaching context.
• Comparing metric and imperial results when a scale report uses the other system.
• Preparing talking points before a health check-up with a doctor.

• Use consistent, recent measurements — morning, unfed weight against a fresh height gives the cleanest reading.
• Remember BMI ignores body composition: athletes with high muscle mass can land in Overweight despite low body fat.
• Treat the categories as screening bands, not a diagnosis, and follow up with a healthcare professional for medical advice.
• The imperial tab expects feet and inches separately, so 5'7" goes in as 5 and 7, not 5.7.
• Do not apply adult BMI thresholds to children or pregnant women — the standard ranges do not fit those groups.
• Pair the result with the healthy-weight range stat to set a concrete, measurable goal.

• The healthy-range stats double as a goal calculator — aim inside the band, not at a round number.
• Imperial height uses two fields, so enter 5'10" as 5 feet and 10 inches.
• Results show one decimal place, which is enough for category decisions.
• Switch tabs and re-enter your measurements to compare metric and imperial readings of the same person.