BMI Is a Screening Tool, Not a Diagnosis
What the metric can show, what it misses, and when more context is needed.
What it does and when to use it
BMI compares weight with height and provides a simple population measure. It does not directly measure fat or account for body composition, age, or fat distribution.
What information to enter
Measure height and weight consistently. Do not mix units or draw medical conclusions from one reading.
How to understand the result
Ranges can signal a need for further review. Athletes, older adults, children, and pregnancy require different context.
Recommended step-by-step workflow
- Check the assumptionsBMI compares weight with height and provides a simple population measure. It does not directly measure fat or account for body composition, age, or fat distribution.
- Use matching unitsMeasure height and weight consistently. Do not mix units or draw medical conclusions from one reading.
- Compare with another scenarioRanges can signal a need for further review. Athletes, older adults, children, and pregnancy require different context.
Short example
Two people with BMI 27 can have very different body composition and health profiles.
Common mistakes
- Treating BMI as a direct body-fat measurement.
- Changing treatment or diet based on BMI alone.
Frequently Asked Questions
Is BMI useful?
Yes as a broad screening tool, especially alongside other measures and history.
What else can be checked?
Waist size, blood pressure, lab results, fitness, and professional assessment.
Are my personal inputs saved?
No. The calculators and guides are designed for quick browser use without storing your personal input values.