Calculator Tools
Calculate body mass index from metric or imperial measurements and see standard adult screening categories for ages 20 and older. The page explains the formula, limits and official methodology without presenting BMI as a diagnosis.
Settings
Measurements
Simple workflow
How to use BMI Calculator
- 1Choose metric or imperial units and enter weight and height.
- 2Select Calculate BMI to see the result and standard adult category.
- 3Read the formula, limitations and linked CDC methodology before interpreting the estimate.
Good to know
Frequently asked questions
What formula is used for BMI?
Metric BMI is kilograms divided by metres squared. Imperial BMI is 703 multiplied by pounds, divided by inches squared.
Who are the standard adult categories for?
The categories shown are intended for adults aged 20 and older. Children and teens require age- and sex-specific percentile methods.
Can BMI diagnose a health condition?
No. BMI is a screening measure, not a diagnosis, and it does not directly measure body fat. Clinical assessment may consider medical history, body composition and other factors.
Are my height and weight stored?
No. The calculation runs locally in the browser. UtilSprout does not upload or store the measurements.
Practical guide
Use adult BMI as a screening measure
Metric BMI is weight in kilograms divided by height in metres squared. Imperial BMI is 703 × weight in pounds divided by height in inches squared. The displayed standard adult categories are intended for adults aged 20 and older.
BMI is a screening measure, not a diagnosis. It does not directly measure body fat or account for factors such as muscle mass, body composition, pregnancy or every population-level difference. Health assessment can require additional information from a qualified professional.
Worked example
Calculate a metric BMI
- Start with
- Enter 70 kg and 175 cm.
- Choose
- Choose Metric and select Calculate BMI.
- You get
- BMI = 70 ÷ 1.75² = 22.9, which is in the standard Healthy weight adult screening category.
Tips for a useful result
- For adults 20+, the standard ranges are under 18.5, 18.5 to under 25, 25 to under 30, and 30 or above.
- Children and teens need age- and sex-specific percentiles; this adult calculator is not designed for them.
- Measurements are processed locally and are not saved. Do not use the result as a medical diagnosis or treatment recommendation.
Sources and methodology
The formula, age scope, category boundaries and screening-language on this page follow the US Centers for Disease Control and Prevention's public adult BMI guidance. External sources are provided for methodology, not as endorsements of UtilSprout.
Authoritative external sources
- CDC: Adult BMI Categories (external)
Official adult 20+ category thresholds and screening guidance.
- CDC: About Body Mass Index (external)
Official explanation of BMI uses and limitations.
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