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Calculate your Body Mass Index (BMI) and assess your health status based on height and weight. Ideal for personal health monitoring.
Adult BMI is kg/m². Categories do not assess children or pregnancy, diagnose illness or measure body fat. Japanese pages use Japan’s obesity classes starting at 25; categories use the unrounded value. Reference
Enter your height and weight to view BMI analysis.
< 18.5
May indicate malnutrition or other health problems.
18.5 - 24.9
Lowest risk of weight-related diseases.
≥ 25
Increased risk of heart disease, diabetes, and other conditions.
Overview
Understand what the tool solves, how it works, and the boundaries of its data.
Body mass index (BMI) relates weight to height. It is a screening measure used to group adult weight status; it is not a direct measurement of body fat and does not describe a person’s full health. This calculator returns a BMI value, a category, and a general category message from the height and weight you enter.
Metric: BMI = weight in kilograms ÷ height in meters²
US customary: BMI = 703 × weight in pounds ÷ height in inches²
In metric mode, enter height in centimeters and weight in kilograms. In US customary mode, height is entered as total inches and weight as pounds. For example, 5 ft 9 in is 69 inches; enter 69, not separate feet and inches. The displayed BMI is rounded to one decimal place, while the category is selected from the unrounded calculation.
| Unrounded BMI (kg/m²) | Tool category |
|---|---|
| Below 18.5 | Underweight |
| 18.5 to below 25 | Healthy weight |
| 25 to below 30 | Overweight |
| 30 or above | Obesity |
These are the adult screening thresholds published by the CDC for people age 20 and older. This page does not ask for age and does not calculate child or teen BMI-for-age percentiles. A rounded display may appear to equal a boundary even when the category was selected using the more precise value.
Guide
Follow the workflow and verify inputs and outputs with practical examples.
Changing systems clears the current height and weight, so select the units before entering measurements.
For metric, use centimeters and kilograms. For US customary, use total inches and pounds. Both values must be greater than zero for a result to appear.
The result updates from your entries. The number is shown to one decimal place; use the category as a broad adult screening classification rather than a diagnosis.
Example: at 69 inches and 160 lb, 703 × 160 ÷ 69² ≈ 23.6, which falls in the tool’s 18.5-to-below-25 category. Reset clears the two measurements.
Use cases
See how the tool fits into real work and everyday tasks.
An adult can calculate a screening value from recent measurements and bring it to a clinician as one topic for discussion.
Use the same unit system and measurement approach over time when tracking a trend; a single value is only one piece of context.
Use the thresholds to see how the tool labels a result, then consider the wider health context with a qualified professional.
Q&A
Find concise answers to common questions and confusing cases.
No. It gives adult category labels and does not calculate BMI-for-age percentiles. CDC guidance uses age- and sex-specific percentiles for ages 2 through 19.
BMI uses only height and weight, so it cannot distinguish muscle from fat or show where fat is carried. A category should not be treated as a complete assessment of an individual.
The value is rounded for display, but the category is chosen from the unrounded result. Near a cutoff, those can look slightly different.
Notes
Review scope, result limitations, and important precautions before use.
BMI is one potential health indicator, not a diagnosis or a complete measure of health. Discuss questions about your result with a health care professional.
Related
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