Find Your Body Mass Index
Calculate your BMI and healthy weight range in seconds — just enter your height and weight, no sign-up required.
Your Results
Two Numbers, One Quick Screening Score
No special equipment needed — just your height and weight.
Choose Your Units
Pick US (feet/inches and pounds) or Metric (centimeters and kilograms), whichever is easiest for you.
Enter Height & Weight
Type in your current height and weight above — no other measurements are needed for a standard BMI.
Get Your Results
Instantly see your BMI value, which WHO category it falls into, and your healthy weight range for your height.
What Is BMI?
Body Mass Index (BMI) is a simple ratio of your weight to the square of your height. It was designed in the 19th century as a population-level screening tool, and today it's used by doctors, researchers, and public health bodies as a quick, free way to flag whether someone's weight may be putting their health at risk.
BMI's biggest limitation is that it can't tell the difference between muscle and fat. A muscular athlete and a sedentary person of the same height and weight will get the identical BMI score, even though their body composition — and health risk — can be very different. That's why BMI works best as a starting point, not a final verdict, and pairs well with a more detailed metric like body fat percentage.
Why BMI Is Still Widely Used
It's Fast and Free
BMI only needs height and weight, so it can be calculated anywhere in seconds without special tools or training.
It Correlates with Health Risk
At a population level, higher BMI is statistically linked to higher rates of heart disease, type 2 diabetes, and other conditions.
It's a Useful Starting Point
BMI is a good first screen that tells you whether a closer look — like a body fat or metabolic age check — might be worthwhile.
How BMI Is Calculated
The formula is the same worldwide — only the units of measurement change.
BMI (Metric)
BMI = weight (kg) ÷ height (m)²
Uses kilograms & metersBMI (Imperial)
BMI = weight (lbs) × 703 ÷ height (in)²
Uses pounds & inchesWHO Adult BMI Categories
These standard ranges apply to most adults aged 20 and over.
Swipe to see all columns →
| Category | BMI Range | What It Means |
|---|---|---|
| Underweight | Below 18.5 | May indicate insufficient nutrition or an underlying health issue |
| Normal weight | 18.5 – 24.9 | Associated with the lowest average health risk |
| Overweight | 25.0 – 29.9 | May carry a moderately increased health risk |
| Obese | 30.0 and above | Associated with a higher risk of weight-related conditions |
What's a Healthy BMI?
A BMI between 18.5 and 24.9 is classified as "normal weight" by the World Health Organization, but the full picture has more nuance.
| Category | BMI Range |
|---|---|
| Underweight | < 18.5 |
| Normal | 18.5 – 24.9 |
| Overweight | 25.0 – 29.9 |
| Obese I | 30.0 – 34.9 |
| Obese II | 35.0 – 39.9 |
| Obese III | 40.0+ |
What BMI Doesn't Account For
When to Look Beyond BMI
BMI vs. Other Health Metrics
BMI is a starting point, not the full picture. These other metrics fill in gaps that height and weight alone can't capture.
Body Fat Percentage
Metabolic Age
8 Ways to Reach a Healthy BMI
Sustainable change comes from a handful of consistent habits, not extreme short-term measures.
Run a Moderate Calorie Deficit
Aim for roughly 300–500 calories below maintenance — large enough to lose weight, small enough to preserve muscle.
Strength Train Regularly
Resistance training helps preserve and build muscle, which improves body composition even when the scale moves slowly.
Prioritize Protein
Adequate protein intake supports muscle retention and keeps you fuller for longer while managing your weight.
Sleep 7–9 Hours
Poor sleep raises hunger hormones and makes healthy weight management noticeably harder, even with a good diet.
Move More Throughout the Day
Walking and everyday activity (NEAT) burn meaningful calories without adding training fatigue.
Limit Added Sugar & Alcohol
Both are easy sources of excess calories that add up quickly without much satiety.
Track More Than the Scale
Pair BMI with body fat percentage or waist circumference for a fuller picture of your progress.
Be Patient and Consistent
Healthy weight change is typically 0.5–1% of bodyweight per week — small, steady changes that actually stick.
Common Questions
Everything you need to know about understanding and using your BMI.