What is a healthy BMI?

For adults, a BMI between 18.5 and 24.9 is generally considered the healthy range. BMI is a general screening tool and does not account for muscle mass or body composition.

BMI Calculator — Free Body Mass Index Calculator (Metric & Imperial)

Q: How is BMI calculated?

BMI equals your weight in kilograms divided by your height in metres squared (kg/m²). This tool also accepts imperial units and converts for you.

Understand your Body Mass Index

BMI (Body Mass Index) is a quick screening number that relates your weight to your height. It's widely used as a general guide to whether your weight is in a healthy range. This calculator works in both metric and imperial units and shows your category the moment you enter your details.

BMI categories (adults)

Under 18.5 — Underweight
18.5 – 24.9 — Healthy weight
25 – 29.9 — Overweight
30 and above — Obese

Note: BMI is a general indicator, not a diagnosis. It doesn't distinguish muscle from fat, so very muscular people may read as "overweight" while being perfectly healthy. For personal health advice, talk to a qualified professional.

Frequently asked questions

How is BMI calculated?

BMI = weight (kg) ÷ height (m)². If you use imperial units, this tool converts your feet, inches and pounds first, then applies the same formula.

What's a healthy BMI?

For most adults, 18.5 to 24.9 is considered the healthy range. It's a general guide, not a personal medical assessment.

Is my data private?

Yes. Nothing you enter is uploaded or stored — the calculation happens entirely in your browser.