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BMI Calculator โ Free Online Tool
Body Mass Index is a simple screening number that compares your weight with your height. This BMI calculator asks for your weight in kilograms and your height in centimetres, then shows your BMI to one decimal place and the category it falls into: underweight below 18.5, normal from 18.5 to 24.9, overweight from 25 to 29.9, and obese at 30 or above. These are the standard World Health Organization adult cut-offs and the formula is weight in kilograms divided by height in metres squared. A person who weighs 70 kg and is 175 cm tall has a BMI of 22.9, which sits in the normal range. BMI is a quick starting point rather than a diagnosis, because it cannot tell muscle from fat, and it ignores age, sex and where weight is carried. Many Indian and Asia-Pacific guidelines also suggest lower thresholds, typically 23 for overweight and 25 for obesity, because South Asians can face higher metabolic risk at a lower BMI, so discuss your result with a doctor or dietitian. The calculator is not for children, whose BMI is read against growth charts. It updates as you type, works on any phone and keeps your data in your browser.
Use our BMI Calculator on AllConvertor โ no registration, no download, works on iPhone, Android, Windows, and Mac. All processing runs in your browser when possible for maximum privacy and speed.
How to use BMI Calculator
- Enter your weight in kilograms.
- Enter your height in centimetres.
- Read your BMI value shown instantly.
- Check the category label below the number and consult a doctor for advice.
Key benefits
- โ 100% free โ no paywall or trial limits
- โ No account or email required
- โ Mobile-friendly responsive design
- โ Instant results in your browser
- โ Secure โ data stays on your device
- โ Trusted by thousands of users daily
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Frequently Asked Questions
How is BMI calculated?
BMI = weight in kilograms รท (height in metres)ยฒ. For 70 kg and 1.75 m, BMI is 70 รท 3.0625 = 22.9.
What is a normal BMI range?
A BMI from 18.5 to 24.9 is considered normal by WHO standards. Below 18.5 is underweight, 25 to 29.9 is overweight and 30 or above is obese.
Is the BMI range different for Indians?
Several Indian and Asia-Pacific guidelines use lower cut-offs, about 23 for overweight and 25 for obesity, because of higher health risk at lower BMI in South Asians. This calculator shows the standard WHO categories, so consider your result alongside advice from a doctor.
Is BMI accurate for athletes and bodybuilders?
Not always. Muscle weighs more than fat, so a muscular person may show a high BMI despite low body fat. Waist size and body-fat percentage give a better picture.
Can I use this BMI calculator for children?
No. Children and teenagers are assessed using age- and sex-specific growth charts, so a paediatrician should interpret their BMI.