BMI calculator
Enter your weight and height to find your BMI and its category.
BMI is a general guide: it does not account for muscle mass, age or sex. For advice about your health, talk to a healthcare professional.
How to calculate your BMI
Body mass index is calculated by dividing your weight in kilograms by your height in metres squared. For example, 70 kg at 1.75 m: 70 ÷ (1.75 × 1.75) ≈ 22.9.
Interpreting your BMI (WHO categories)
Under 18.5: underweight. From 18.5 to 24.9: normal weight. From 25 to 29.9: overweight. From 30: obesity. These thresholds are guides for adults.
The limits of BMI
BMI does not tell muscle mass from fat mass, and ignores age, sex and where fat is stored. A very muscular athlete can have a high BMI without excess fat. For a reliable assessment, talk to a doctor or a dietitian.
Frequently asked questions
How is BMI calculated?
BMI = weight (kg) ÷ height (m) squared.
What counts as normal weight?
According to the WHO, a BMI between 18.5 and 25. It is a general guide, not a diagnosis.
What is the ideal BMI?
Between 18.5 and 25 for an adult according to the WHO, but it is only a guide.
Is BMI valid for children?
No: for children and teenagers, growth charts are used instead. Ask a paediatrician or doctor for advice.
More free tools
Combine several PDFs into a single file.
Compress a PDFShrink a PDF so you can email it.
Convert images to PDFTurn your photos and scans into a PDF.
Convert a PDF to JPG imagesConvert each page of a PDF into an image.
QR code generatorFree QR code as PNG or SVG.
Compress imagesMake your JPG, PNG and WebP photos lighter.
Password generatorStrong, random password.
Word and character counterWords, characters, social media limits.
Compress videoMake a video lighter without visible loss.
Convert video to GIFTurn a video into an animated GIF.
Trim videoKeep only the right part.
Extract MP3 from a videoGet the sound of a video as MP3.
Percentage calculatorX% of Y, percent change and more.
Uppercase and lowercase converterSwitch text case in one click.
Age calculatorYour exact age and next birthday.
Calorie calculatorYour daily calorie needs to lose, maintain or gain weight.
Ideal weight calculatorYour ideal weight and normal weight range.
Water intake calculatorHow much water to drink each day.
Sleep calculatorThe best bedtime or wake-up time.
Grade average calculatorWeighted average and the grade you need next.
Unit converterLength, weight, volume, temperature and more.
Days between two datesDays between dates and date arithmetic.
Extract pages from a PDFKeep only the pages you need.
Rotate a PDFRotate all pages or just a few.
Add page numbers to a PDFNumber the pages of your PDF.
Add a watermark to a PDFPut a watermark on every page.
Delete pages from a PDFRemove the pages you don’t need.
Crop a PDFTrim the margins of your PDF.
Protect a PDF with a passwordLock your PDF with a password.
Remove a PDF passwordUnlock a PDF whose password you know.
Due date and ovulationOvulation window and estimated due date.
Ovulation calculatorOvulation date and fertile window.
Period calendarYour next periods at a glance.
Pregnancy week calculatorHow many weeks pregnant you are.
Conception date calculatorEstimate when conception happened.
Macro calculatorYour daily macros in grams.
Random name pickerDraw winners from a list.
YouTube thumbnail in HDGrab any YouTube thumbnail.
Stylish bio and username generatorFancy fonts for your bio.
Convert an imageConvert images between formats.
Scan a QR codeRead any QR code.
Currency converterConvert 25+ currencies live.
Online translatorTranslate text into 30+ languages.
Translate a PDFTranslate a PDF page by page.
Loan payment calculatorMonthly payment and total loan cost.