Calculators / TOOLKIT
BMI Calculator
Your Body Mass Index, category and healthy weight range - metric or imperial.
Free to use · No account needed
How to use
- Choose metric or imperial units.
- Enter your height and weight - results update instantly.
- See your BMI, WHO category, position on the scale, and healthy weight range for your height.
Body Mass Index is a quick health screening metric. Calculate your BMI from height and weight, see which category you fall into and get context for what it means. A useful baseline for fitness goals, though not a substitute for medical advice.
Use cases
1. Use case: Track a fitness goal Record your BMI at the start and end of a weight-loss program to see progress objectively, in metric or imperial units.
2. Use case: Screen before a health check Quickly estimate your BMI category before a medical appointment so you can discuss it with context.
Practical tips
BMI is a population screening number, not a diagnosis: it ignores muscle mass, bone density and fat distribution, which is why athletes often score 'overweight'. Enter height and weight in one unit system consistently — mixing metric and imperial inputs is the most common error. Children and teenagers need age- and sex-specific percentile charts, not the adult ranges shown here. Use the result as a prompt for a conversation, not a verdict. Like every tool on this site, the Bmi Calculator runs entirely in your browser: the data you enter never leaves your device, nothing is uploaded to a server, and the tool keeps working if your connection drops.
Common mistakes
BMI is a screening statistic; most misuse is over-reading it:
- Mixing unit systems — entering height in centimeters and weight in pounds produces a wrong number that still looks plausible.
- Reading BMI as a diagnosis instead of a population screening number; it ignores muscle mass, bone density and fat distribution.
- Applying adult ranges to children or teenagers, who need age- and sex-specific percentile charts instead.
- Comparing your number to other people's rather than tracking its own trend over time.
Why use this tool
Get the most value by using it the way screening tools are meant to be used:
- Establishing a baseline to track over time, rather than judging a single reading.
- Screening a group or population, where the ranges are designed to apply.
- Framing a health conversation with real numbers before a professional weighs in.
- Checking where a weight goal would land on the scale before committing to it.
Frequently asked questions
Does the Bmi Calculator send my data anywhere?
No. It runs entirely in your browser — your input is processed on your device and never uploaded. Refresh the page and it still works offline.