Calculate BMI

Calculate adult BMI from weight and height. For ages 20 and older.

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Calculate BMI processes your input in this browser. Inputs and results are excluded from analytics. Recent tools save tool names, visit counts and last-visit times. Saved tools store only their names. Draft saving is optional and stays on this device; delete saved text with the draft controls. Loading text from a URL is optional and contacts that server; its URL and your IP address are visible to the server. An optional “Use in” action keeps a handoff in this tab. The next tool removes it on arrival and ignores it if more than a minute has passed.

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Weight (lb)

Height (inches)

More inputs and assumptions

Age (years)

Answer

…

BMI = weight in kilograms ÷ height in meters squared. Pounds convert to kilograms by 0.45359237; inches convert to meters by 0.0254.

More results

Precision and calculation record

Decimal places in numeric results and text downloads

Rounding changes displayed numbers, not the calculation. Text, fractions, matrices and CSV schedules keep their own formatting. Automatic keeps up to 12 significant digits, with money shown to cents where applicable.

Saved scenario

Save the current answer, then change an input to compare. This clears when you leave.

Formula and assumptions

For adults 20 and older. BMI is one screening measure, not a diagnosis or an individual health assessment. It does not measure body fat directly. Discuss its meaning with a health professional; child and teen BMI needs a different method.

Automatic precision shows numbers to 12 significant digits. Thousands separators such as 1,000 are accepted; use a dot for decimals.

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Updated 2026-09-26

Using Calculate BMI

BMI = weight in kilograms ÷ height in meters squared. Pounds convert to kilograms by 0.45359237; inches convert to meters by 0.0254.

Next: Basic calculator

A worked example

With weight (lb) = 150, height (inches) = 68, age (years) = 30, the bmi is 22.807187920820478.

Before you use the result

Example results for weight (lb)

These examples use Height (inches): 68; Age (years): 30. They are reference calculations, not recommended settings.

Weight (lb)	BMI
75	11.4035939604
150	22.8071879208
300	45.6143758416

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ToolOctopus. “Calculate BMI.” Updated 2026-09-26. https://tooloctopus.com/bmi-calculator.

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