BMI & Waist-to-Height Calculator

How this tool works

BMI is weight in kilograms divided by height in metres squared. The categories shown use CDC adult thresholds for people aged twenty and older. Waist-to-height ratio divides waist circumference by height, using the same units. These are screening measures rather than diagnoses and do not directly measure body fat. They are not appropriate for assessing pregnancy or children. Muscle mass, ethnicity and other factors can affect interpretation. Measure consistently and discuss health concerns with a qualified clinician rather than changing treatment based on a number.

What is a healthy waist-to-height ratio?

A common guideline is to keep your waist measurement below half your height, a ratio under 0.5. It is a screening measure, not a diagnosis.

Why check waist-to-height as well as BMI?

BMI uses only height and weight, so it cannot tell muscle from fat or show where fat is carried. Waist size adds information about fat around the middle.

Is BMI accurate for athletes, children or older adults?

BMI can mislead for very muscular people, and children need age- and sex-specific charts. Ask a health professional to interpret your results.

How do I get a useful result?

Start by reading the field labels and the method above. Replace the example values with information that matches your own situation, then use the main button to generate the result. Review the units, dates and any assumptions before copying or printing it. If you change an input, run the tool again so the output reflects your latest choices. An example is a starting point for learning the controls, not a recommendation for your circumstances.

Does this page upload my information?

This tool performs its work in your browser. Its input values are not submitted to a server by the calculator. Closing or reloading the page clears unsaved work. Checklist pages offer an explicit browser-save option; that storage belongs to this browser and device and may be cleared by private browsing or browser settings. Downloads, printed pages and copied text contain whatever information you included, so keep them somewhere appropriate.

Can I use it on a phone?

The form and result panels adapt to a smaller screen. Use your device’s normal keyboard to enter values, and review the output before sharing it. The print button opens the browser’s print controls, where available. Printing and saving as PDF depend on your operating system. If a feature is unavailable, try a current browser with JavaScript enabled. Keep a separate copy of anything important; the page is not a cloud backup service.

Method reference: Read the source documentation