Body mass index
BMI Calculator
Calculate your Body Mass Index using your height and weight and understand what your result may indicate.
Your BMI
0.0 Healthy WeightBMI Categories
Healthy BMI Range: 18.5 – 24.9
BMI is a general screening tool and does not directly measure body fat or overall health.
The basics
What Is BMI?
Body Mass Index (BMI) is a simple measurement that compares body weight with height. It is often used as a general screening tool to group results into broad weight categories.
BMI can provide a useful starting point, but it does not describe a person’s complete health or directly measure body fat. Your result should be considered alongside other information and personal circumstances.
The formula
BMI = weight (kg) ÷ height² (m)
How Is BMI Calculated?
BMI is calculated by dividing weight in kilograms by height in meters squared. When pounds and feet are entered, this calculator first converts them to kilograms and centimeters.
Metric BMI Formula
Convert height from centimeters to meters, multiply that height by itself, then divide weight by the result.
Result ranges
BMI Categories
The following ranges are commonly used for adult BMI screening. They are broad reference categories, not diagnoses.
| Category | BMI Range |
|---|---|
| Underweight | Below 18.5 |
| Healthy Weight | 18.5–24.9 |
| Overweight | 25.0–29.9 |
| Obesity | 30.0 and above |
Understanding the number
Below 18.5
18.5–24.9
25.0–29.9
30.0 and above
What Does Your BMI Mean?
A BMI category offers general context for your height-to-weight ratio. It cannot determine the reason for a result or assess health by itself.
Underweight
This range indicates a lower weight relative to height. Individual build and circumstances still matter.
Healthy Weight
This is the commonly referenced BMI range for adults, though BMI remains only one general measure.
Overweight
This range indicates a higher weight relative to height. BMI alone cannot show how much of that weight is muscle or fat.
Obesity
This is the highest standard BMI category. A qualified professional can provide more individualized context when needed.
Important context
Limitations of BMI
BMI uses only height and weight. It does not distinguish between several factors that can meaningfully change how a result should be interpreted:
- Muscle and fatBMI cannot tell whether body weight comes primarily from muscle or body fat.
- Bone massDifferences in frame size and bone mass are not included in the calculation.
- Body compositionThe formula does not measure the proportions of fat, muscle, bone, and other tissue.
- Fat distributionBMI does not show where body fat is carried.
Athletes and highly muscular people may have a high BMI even when their body fat percentage is relatively low.
Two different measures
BMI
Body Fat
BMI vs Body Fat Percentage
BMI compares total weight with height. Body fat percentage estimates how much of total body weight is fat tissue. The measurements answer different questions and each has its own limitations.
Weight relative to height
Quick to calculate from two measurements, but unable to distinguish muscle from fat.
Calculate your BMIEstimated fat proportion
Uses additional measurements to estimate the percentage of body weight made up of fat.
Try the Body Fat Calculator
Common questions
Frequently Asked Questions
What is a healthy BMI?
For adults, a BMI from 18.5 to 24.9 is commonly described as the healthy weight range. This is a general screening range and does not define overall health.
Is BMI accurate?
BMI accurately expresses weight relative to height, but its usefulness for an individual is limited because it does not account for body composition, frame size, or fat distribution.
Does BMI measure body fat?
No. BMI is calculated only from height and weight. It does not directly measure body fat percentage.
Can muscular people have a high BMI?
Yes. Muscle contributes to body weight, so a highly muscular person may have a BMI in a higher category despite having relatively low body fat.
Is BMI different for men and women?
The standard adult BMI formula and category ranges are the same for men and women. However, body composition can differ, so BMI may not provide the same context for every person.
How often should I calculate my BMI?
BMI does not need frequent recalculation. Checking it after a meaningful weight change is generally more useful than tracking small day-to-day changes.
Important: volcaprint calculators provide estimates for educational purposes only. BMI is a general screening measure and should not replace professional medical advice.