Body Mass Index (BMI) is one of the most widely used measurements to assess whether a person has a healthy body weight for their height. But what does your BMI actually mean — and what should it be?
In this guide, we’ll explain BMI ranges, share a full BMI chart for men and women, and show you how to calculate yours in seconds.
What Is BMI?
BMI stands for Body Mass Index. It’s calculated by dividing your weight in kilograms by your height in metres squared:
BMI = weight (kg) ÷ height (m)²
For example, if you weigh 70kg and are 1.75m tall: BMI = 70 ÷ (1.75 × 1.75) = 22.9
BMI Chart: What Do the Ranges Mean?
| BMI Range | Category |
|---|---|
| Below 18.5 | Underweight |
| 18.5 – 24.9 | Healthy weight |
| 25.0 – 29.9 | Overweight |
| 30.0 – 34.9 | Obese (Class I) |
| 35.0 – 39.9 | Obese (Class II) |
| 40.0 and above | Severely obese (Class III) |
Healthy BMI for Men vs Women
The BMI ranges above apply to both men and women. However, women naturally carry more body fat than men at the same BMI due to physiological differences. This means a woman with a BMI of 22 and a man with a BMI of 22 may have different body fat percentages despite being in the same “healthy” category.
For this reason, BMI is a useful screening tool but shouldn’t be used in isolation. A body fat calculator can give you a more complete picture.
BMI Limitations
BMI has some well-known limitations:
- Muscle mass — Athletes and muscular people may have a high BMI but very low body fat
- Age — Older adults tend to have more body fat at the same BMI as younger adults
- Ethnicity — Some ethnic groups face higher health risks at lower BMI thresholds
- Height extremes — Very tall or short individuals may get misleading results
Calculate Your BMI Free
Use our free BMI calculator to find your BMI instantly. Just enter your height and weight, and you’ll get your BMI score along with which category you fall into — no maths needed.
Frequently Asked Questions
What is a healthy BMI for a woman?
A healthy BMI for women is between 18.5 and 24.9, the same as for men. However, women generally have higher body fat percentages at the same BMI due to natural physiological differences.
What BMI is considered obese?
A BMI of 30 or above is classified as obese. This is further divided into Class I (30–34.9), Class II (35–39.9), and Class III or severe obesity (40 and above).
Is BMI accurate?
BMI is a useful general indicator but not perfectly accurate for everyone. It doesn’t account for muscle mass, bone density, age, or fat distribution. Use it alongside other health metrics for a complete picture.
Check your BMI now with our free BMI calculator — instant results, no sign-up required.