Calculate your Body Mass Index and see your healthy weight range
| Category | BMI Range | Status |
|---|---|---|
| Underweight | Below 18.5 | ⚠️ Caution |
| Normal Weight | 18.5 – 24.9 | ✅ Healthy |
| Overweight | 25.0 – 29.9 | ⚠️ Caution |
| Obese (Class I) | 30.0 – 34.9 | 🔴 Concern |
| Obese (Class II) | 35.0 – 39.9 | 🔴 Concern |
| Obese (Class III) | 40.0 and above | 🔴 Concern |
Select your preferred unit system — metric (kilograms and centimeters) or imperial (pounds, feet, and inches). Enter your weight and height using the input fields or drag the sliders. Click Calculate BMI to instantly see your result, including your BMI category, color-coded scale, and your healthy weight range for your height.
BMI (Body Mass Index) is one of the most widely used screening tools for assessing whether a person is at a healthy weight for their height. Doctors, insurance companies, and public health researchers use it as a starting point for identifying weight-related health risks.
Consider this: a 5'9" person (175 cm) weighing 200 lbs (90.7 kg) has a BMI of 29.7 — just under the obese threshold, but firmly in the "overweight" category. Research consistently links BMIs above 25 with increased risks for type 2 diabetes, cardiovascular disease, and hypertension. Meanwhile, a BMI below 18.5 is associated with nutritional deficiencies, osteoporosis, and a weakened immune system.
BMI is especially useful for population-level health trends and as a quick self-check tool. Athletes and very muscular individuals may show a high BMI despite low body fat — which is why BMI should always be interpreted alongside other metrics like body fat percentage and waist circumference.
The BMI formula is straightforward:
Metric: BMI = weight (kg) ÷ height (m)²
Imperial: BMI = (weight (lbs) × 703) ÷ height (in)²
For example, a person who is 70 kg and 175 cm tall: BMI = 70 ÷ (1.75)² = 70 ÷ 3.0625 = 22.9 — which falls in the Normal Weight range.
The healthy weight range is calculated by solving the BMI formula in reverse: Weight = BMI × height (m)². Using BMI values of 18.5 and 24.9 gives you the lower and upper bounds of the healthy range for your specific height.
For most adults, a BMI between 18.5 and 24.9 is considered healthy. A BMI of 25–29.9 is classified as overweight, and 30 or above is classified as obese. However, these thresholds can vary slightly for different ethnic groups — for example, health organizations sometimes use lower cutoffs for Asian populations.
BMI is a population-level screening tool and has limitations for individuals. It doesn't differentiate between muscle and fat, so bodybuilders and athletes often show elevated BMI despite having very little body fat. It also doesn't account for where fat is distributed on the body, which significantly affects health risk.
Yes — this is sometimes called "normal weight obesity" or being "skinny fat." A person can have a normal BMI but carry too much visceral fat (fat around the organs), which raises health risks. Waist circumference and body fat percentage provide additional useful information beyond BMI alone.
For most adults not actively trying to change their weight, checking BMI once a year is sufficient. If you're working toward a weight-related health goal, monthly checks help you track meaningful progress. Daily weighing is generally not recommended as weight naturally fluctuates by 1–3 kg throughout the day.