BMI Calculator
Enter your height and weight to get your Body Mass Index (BMI) and category. BMI is a quick screening number, useful as a starting point but blind to muscle versus fat.
Your results
How it works
- 1BMI is your weight in kilograms divided by your height in metres squared.
- 2Categories: under 18.5 underweight, 18.5-24.9 normal, 25-29.9 overweight, 30+ obese.
- 3Because it ignores muscle mass, very muscular people can read as overweight despite low body fat.
Frequently asked questions
What is a healthy BMI?
A BMI between 18.5 and 24.9 is classed as the healthy range for most adults. It is a screening tool, not a diagnosis, so consider it alongside body composition and health markers.
Is BMI accurate for athletes?
Not really. BMI cannot tell muscle from fat, so muscular athletes often score as overweight despite being lean. Use body-fat measurements for a truer picture.
Should I use BMI or body fat percentage?
Body fat percentage describes your composition more accurately, but BMI is faster and needs no special tools. Use BMI as a quick check and body fat for detail.
Using the result
What the number is
An estimate from simple measurements: height, weight or a tape measure. These formulas describe large groups of people well and single bodies less well, because muscle, frame size and where you carry fat all shift the true value.
How to use it
Treat it as a reference point and follow the trend. Measure the same way and at the same time of day every two to four weeks, and look at the direction of change rather than a single reading.
When to stop guessing
If the number and the mirror disagree for months, track your waist, photos and strength alongside it. A coach on Trainera reads them together and adjusts your plan.
What this calculator cannot know
This calculator works from height, sex and, depending on the tool, your weight or a few circumferences. BMI and ideal weight cannot tell muscle from fat, and a tape measure estimate can be off by several percentage points even when you measure carefully. None of them account for ethnicity or bone structure, and they are not meant for children, pregnant women or very muscular athletes. Use the result as a rough reference and talk to a doctor if you are worried about your weight. Nothing here is medical advice.
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Turn these numbers into a real plan
Train on your own with Trainera's free workout and diet tracker, or get matched with a certified personal trainer who builds your plan around these numbers.