How to use Adult BMI
Calculate adult body mass index from height and weight.
- Choose the operation and enter every labeled input, keeping units and the time period consistent.
- Calculate, compare the worked example below and inspect any warnings.
- Change one assumption to compare another scenario; keep the model’s limits in view.
Formula & calculation method
Adult BMI = weight in kilograms ÷ height in metres squared. Imperial inputs are converted using 1 lb = 0.45359237 kg and 1 in = 2.54 cm before calculation.
Input reference · 2 fields
These labels describe the calculation’s base units. Supported measurements can switch through the header’s region settings; follow the current workspace labels. Prefilled values are examples.
- Weight (kg)
- Enter a plain number with a decimal point if needed. The workspace shows an illustrative value, not a recommendation.
- Height (cm)
- Enter a plain number with a decimal point if needed. The workspace shows an illustrative value, not a recommendation.
A quick example
70 kg and 175 cm gives a BMI of approximately 22.9.
Assumptions, edge cases & limits
- The adult screening categories are not designed for children or pregnancy.
- BMI does not directly measure body fat, muscle mass or an individual’s health.
- For adults aged 20 and over. BMI is a screening measure, not a diagnosis; it is not a pregnancy or child growth assessment.
Questions about Adult BMI
Can I calculate adult BMI using pounds and inches?
Yes. Choose US customary or Imperial in the header’s region settings. Weight and height labels change and existing measurements are converted before the standard BMI formula is used.
Does a high BMI prove that I am unhealthy?
No. BMI is one screening measure. Body composition and individual context matter, and the result is not a diagnosis or a personalized weight target.
Are my files or inputs uploaded?
Calculation and file processing run in your browser without a processing upload. Downloads go to your device. Choosing a next-step transfer creates a temporary local copy for that workflow. Region preferences are stored separately from tool inputs. See our privacy details.
Can I use this tool for free?
Yes. No signup, subscription or payment is required to use the tool or download its output. File tools have device and size limits; a smaller batch may work better on a phone.
Method & references
Read the underlying method or measurement convention in context. These references do not imply affiliation or endorsement.
CDC: Adult BMI categories ↗Educational health estimates. No independent clinical review is claimed.A result or explanation needs correcting? Tell us the tool name and an example.