Best BMI Calculator Online
BMI Calculator
Calculate Your BMI
The BMI calculator divides your weight in kilograms by your height in meters squared to give a single number that screens for weight-related health risk. It is a starting point, not a complete picture of health.
BMI Formula
BMI = weight (kg) / height (m)²
Imperial version: BMI = 703 x weight (lb) / height (in)². Example: 75 kg, 1.75 m tall. BMI = 75 / (1.75 x 1.75) = 75 / 3.0625 = 24.5.
BMI Classification Table (WHO)
| BMI Range | Category | Health Risk |
|---|---|---|
| Below 18.5 | Underweight | Malnutrition, bone loss, immune issues |
| 18.5 to 24.9 | Normal weight | Lowest risk for most adults |
| 25.0 to 29.9 | Overweight | Moderate increased risk |
| 30.0 to 34.9 | Obese Class I | High risk |
| 35.0 to 39.9 | Obese Class II | Very high risk |
| 40.0 and above | Obese Class III | Extremely high risk |
BMI Limitations
BMI does not measure body fat directly. A muscular athlete can have a BMI over 25 while carrying very little fat. Older adults can have a normal BMI while still having excess body fat due to muscle loss. BMI also does not account for fat distribution. Abdominal fat carries higher risk than the same amount of fat elsewhere. Use waist circumference alongside BMI for a fuller assessment.
Healthy Weight Range by Height
| Height | Minimum Healthy Weight | Maximum Healthy Weight |
|---|---|---|
| 5'4" (163 cm) | 52 kg / 114 lb | 70 kg / 154 lb |
| 5'6" (168 cm) | 55 kg / 121 lb | 74 kg / 163 lb |
| 5'8" (173 cm) | 59 kg / 130 lb | 79 kg / 174 lb |
| 5'10" (178 cm) | 63 kg / 139 lb | 84 kg / 185 lb |
| 6'0" (183 cm) | 67 kg / 148 lb | 89 kg / 196 lb |
| 6'2" (188 cm) | 71 kg / 157 lb | 95 kg / 209 lb |
Frequently Asked Questions
What is a healthy BMI?⌄
A BMI between 18.5 and 24.9 is considered the normal range for adults by WHO guidelines. Below 18.5 is underweight. Between 25 and 29.9 is overweight. At 30 or above, clinical obesity begins. These thresholds are set for adults and do not apply to children.
Is BMI an accurate measure of health?⌄
BMI is a useful population-level screening tool but has known limitations for individuals. It does not distinguish between muscle and fat, does not account for age or sex differences in body composition, and does not capture fat distribution. Use it alongside waist circumference, body fat percentage, and clinical markers for a complete picture.
What BMI is considered overweight or obese?⌄
A BMI of 25.0 to 29.9 is classified as overweight. A BMI of 30.0 or higher is classified as obese. Obesity is further divided into Class I (30-34.9), Class II (35-39.9), and Class III, sometimes called severe obesity (40+).
How does BMI differ for men and women?⌄
The same BMI thresholds apply to both sexes, but women naturally carry more body fat than men at the same BMI. A woman with a BMI of 22 typically has a higher body fat percentage than a man with the same BMI. Some researchers propose separate thresholds, but WHO and most clinical guidelines still use the same scale.
Can I have a high BMI and still be healthy?⌄
Yes, in some cases. Highly muscular individuals often have BMIs in the overweight or obese range with very low body fat. Research does show that metabolically healthy obesity is possible, but it represents a minority of people with high BMI and carries some long-term risk regardless.