Smart Calculations, Smarter Decisions
Check your body mass index with WHO classification, health risk assessment, and ideal weight range. No registration. Works offline.
Check Your BMI Free →Body Mass Index (BMI) is a screening tool that estimates body fat based on height and weight. It's calculated as weight (kg) divided by height (m) squared. A BMI of 18.5-24.9 is considered normal, 25-29.9 is overweight, and 30+ is obese according to WHO classifications. It's widely used because it requires no special equipment — just a scale and a measuring tape.
However, BMI has important limitations. It doesn't distinguish between muscle and fat (a bodybuilder and an obese person can have the same BMI), doesn't account for age or gender differences in body composition, and uses different thresholds for Asian populations (WHO recommends 23+ as overweight for Asians vs 25+ for Western populations). It's a starting point, not a diagnosis.
Our BMI calculator supports both metric (kg/cm) and imperial (lbs/inches) units, shows your WHO category with health risk interpretation, provides your ideal weight range, and includes Asian-specific thresholds. It takes 2 seconds to check — and while BMI alone isn't definitive, it's a useful data point to track alongside other health metrics.
Here's how the WHO classifies BMI, along with the general health-risk association. Note the separate thresholds recommended for Asian populations, who face elevated risk at lower BMIs:
| Category | BMI (General) | BMI (Asian) |
|---|---|---|
| Underweight | Below 18.5 | Below 18.5 |
| Normal | 18.5 – 24.9 | 18.5 – 22.9 |
| Overweight | 25.0 – 29.9 | 23.0 – 27.4 |
| Obese | 30.0 and above | 27.5 and above |
Example: a person who is 170 cm and 75 kg has a BMI of 25.9 — "overweight" on the general scale, and firmly overweight on the Asian scale. Dropping to 68 kg would bring them to 23.5, into the normal range on the general scale.
Because BMI can't tell muscle from fat, doctors often pair it with these simple measures:
Use BMI as a quick screen, then add waist measurement for a fuller picture. If your BMI flags a concern, that's a prompt to talk to a healthcare professional — not a diagnosis on its own.
BMI is calculated by dividing your weight in kilograms by your height in meters squared: BMI = weight (kg) / height (m)². For imperial units: BMI = (weight in lbs × 703) / (height in inches)².
According to the WHO, a healthy BMI is between 18.5 and 24.9. Below 18.5 is underweight, 25-29.9 is overweight, and 30+ is obese. BMI doesn't account for muscle mass, age, or body composition.
Yes, completely free with no registration. Your data never leaves your device — all calculations happen locally in your browser. It even works offline.
Research shows people of Asian descent tend to develop health risks like type 2 diabetes and heart disease at lower BMI levels than Western populations, due to differences in body composition and fat distribution. The WHO therefore recommends a lower "overweight" threshold of 23 (vs 25) and "obese" at 27.5 (vs 30) for Asian populations. Our calculator shows both scales.
Yes. BMI doesn't distinguish muscle from fat, so athletes and muscular individuals often register as "overweight" or "obese" despite low body fat. Conversely, someone with a "normal" BMI can carry unhealthy visceral fat. That's why BMI should be paired with waist circumference, body-fat percentage, and overall fitness — not treated as a standalone verdict.