Free BMI Calculator — Why BMI Alone Is Incomplete

Last updated: April 17, 2026

MoneyMath's BMI calculator calculates BMI and waist-to-height ratio together, showing where BMI can be useful as a screening measure and where it can misclassify individual health.

Free to useRuns in your browserSource-backed assumptions

Calculate BMI from height and weight, then compare it with waist-to-height ratio for more context.

See the healthy weight range and where BMI categories can misclassify muscular or older adults.

Use BMI as a screening signal, not a complete diagnosis of health.

How to use this calculator

Step 1Enter your starting information. Add the core inputs requested by the BMI Calculator, such as amounts, dates, rates, income, weight, or other scenario details.
Step 2Review the calculated result. Read the headline answer first, then scan the supporting breakdown, chart, or comparison table.
Step 3Compare another scenario. Change one input at a time to understand what drives the result and which option is most realistic.

Formula, Sources & Assumptions

Formula

BMI = weight in kilograms divided by height in meters squared; imperial inputs are converted before calculating.

Assumptions

BMI is a screening tool and does not diagnose health or body composition.
Waist-to-height ratio adds context but is still not a medical diagnosis.

Sources

CDC adult BMI guidanceBMI categories and screening limitations.