BMI Calculator – Calculate Your Body Mass Index Instantly
Please enter a valid height and weight.
What Is BMI?
Body Mass Index (BMI) is a simple screening measurement that uses your height and weight to estimate whether your weight falls into a healthy range. It’s widely used by doctors and health organizations as a quick starting point for assessing weight-related health risk, though it doesn’t measure body fat directly.
BMI Formula
Metric: BMI = weight (kg) ÷ height (m)²
Imperial: BMI = [weight (lb) ÷ height (in)²] × 703
How to Use This BMI Calculator
Select your preferred unit system (Imperial or Metric), enter your height and weight, then click “Calculate BMI.” Your result will show instantly along with your BMI category and a visual indicator of where you fall on the scale.
BMI Categories
| BMI Range | Category |
|---|---|
| Below 18.5 | Underweight |
| 18.5 – 24.9 | Normal Weight |
| 25.0 – 29.9 | Overweight |
| 30.0 and above | Obese |
Limitations of BMI
BMI is a useful general screening tool, but it doesn’t distinguish between muscle and fat mass. Athletes and very muscular individuals may score in the “overweight” range despite having low body fat. It also doesn’t account for age, sex, bone density, or fat distribution. If you’re pregnant, BMI isn’t the right metric to track — use our Pregnancy Calculator instead to follow your weight gain timeline properly.
Frequently Asked Questions
What is a healthy BMI?
A BMI between 18.5 and 24.9 is generally considered a healthy range for most adults.
Is BMI accurate for everyone?
No. BMI doesn’t account for muscle mass, bone density, or fat distribution, so it may be less accurate for athletes, older adults, and pregnant women.
How often should I check my BMI?
Checking every few months is enough for most people, unless you’re actively tracking a fitness or weight goal.
Does BMI apply to children?
No, children and teens require age- and sex-specific BMI percentile charts, not the standard adult BMI formula.