BMI Calculator
Determine your Body Mass Index (BMI) based on your height and weight to identify your weight category.
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Calculator guide
BMI Calculator
Calculate body mass index from height and weight and see the corresponding value or category provided by the page. BMI is a screening measure based on two inputs; it does not directly measure body fat or describe a person's overall health.
How to use the calculator
- 1Choose the height and weight units requested by the fields and enter current measurements.
- 2Calculate BMI and read the number and any category shown by the tool.
- 3Use the result as one data point only, and talk with a health professional if you need a personal assessment.
Important details to understand
1.Start with the right inputs
Check every number, date, unit, and selected mode before calculating. A correct formula can still give a misleading answer when an input is missing, entered in the wrong unit, or based on a different time period.
2.Know what the calculation includes
The method below describes what this tool uses. Real situations can involve extra rules, costs, calendar conventions, or personal details that are not part of the form, so compare the assumptions with your actual question.
3.Read the unit and rounding
Look at the label as well as the displayed number. Rounding can change the last digits, and results in different units or time periods are not directly comparable until you convert them consistently.
4.Treat the result as a useful check
Use the output to understand a calculation, explore a scenario, or make an initial estimate. When a result affects a formal deadline, a health decision, a contract, or a large payment, confirm it with the relevant source or qualified professional.
How the calculation works
BMI is mass in kilograms divided by height in meters squared: BMI = kg/m². When customary units are selected, the calculation converts them before applying the formula. A category label is based on the page's configured ranges.
A worked example
For 70 kg and 1.75 m, BMI is 70 ÷ (1.75 × 1.75), or about 22.9.
When this calculator is useful
Get a quick standardized index for a general overview or to compare measurements over time using the same method.
Planning ahead
Try a few realistic input values to see how a change in an amount, measurement, date, or rate affects the answer.
Learning the method
Follow the explanation and example to understand which inputs matter and how they are combined.
Checking your own work
Compare the result with a hand calculation, a worksheet, or a trusted source when you need an independent sense check.
Explaining a result
Keep the original inputs and units with the output so another person can understand what was calculated.
Tips for a more reliable answer
- Enter the values from the same source and keep units consistent throughout the calculation.
- Check that you selected the mode or option that matches the question you are trying to answer.
- Use the worked example to confirm you understand the inputs and the kind of result the tool returns.
- Save the inputs with the result so you can review or repeat the calculation later.
Limitations and assumptions
BMI does not distinguish muscle from fat, show fat distribution, or fully account for age, pregnancy, or individual differences. A category is not a diagnosis. Use a clinician's guidance for health decisions.
Every result depends on the information entered and the method described above. The calculator cannot confirm that the inputs are complete or that its assumptions match a particular provider, policy, location, body, or real-world situation.
Frequently asked questions
Does BMI measure body fat?
No. It uses height and weight and cannot distinguish muscle, bone, or fat.
Can children use adult BMI categories?
Children require age- and sex-specific assessment; do not apply adult ranges to them.
Should I make a health decision from this number alone?
No. It is one screening measure and should be considered with professional guidance.
Why might my result differ from another calculator?
Tools can use different assumptions, units, date conventions, included costs, or rounding rules. Compare the inputs and method descriptions before deciding that one result is wrong.
What should I check if the answer looks wrong?
Review the selected mode, each entered value, the units, and any optional fields. Then compare a simple example with the method described in this guide.
Can I rely on the result for an official or high-impact decision?
Use the result as an estimate or explanation and check the limitations listed for this tool. Confirm important decisions with the relevant official source or a qualified professional.