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Calculate your Body Mass Index (BMI) and find your weight category.
Our free BMI calculator instantly computes your Body Mass Index using your height and weight. See whether you're in a healthy weight range and what your BMI category means. The calculator is designed to give a fast answer, but the quality of the answer still depends on accurate inputs and a clear idea of what decision you are trying to support.
- Enter Weight and Height using the same units you plan to compare or report.
- Read the main bmi first, then use the supporting outputs to understand the trade-offs behind that result.
- Compare your numbers with the worked examples below if you want a quick reasonableness check.
BMI gives a quick screening signal, not a full body-composition diagnosis. The category helps you place the number in standard public-health ranges. On this page, the primary output is bmi.
Scenario 1: 70 kg, 175 cm. Inputs used: weight: 70, height: 175. Example result: 22.9 (Normal). A person weighing 70 kg and standing 175 cm tall has a BMI of 22.9, which falls in the normal/healthy weight range. Scenario 2: 90 kg, 170 cm. Inputs used: weight: 90, height: 170. Example result: 31.1 (Obese). A person weighing 90 kg and 170 cm tall has a BMI of 31.1, which falls in the obese category (≥30).
Core formula: BMI = weight / (height in meters)^2. Body mass index compares your weight to your height to place the result in standard weight-status ranges.
- Height is converted from centimeters to meters before squaring.
- The category changes at the standard thresholds 18.5, 25, and 30.
Use BMI when you want a fast first-pass assessment of weight relative to height or when comparing broad changes over time. Related paths for follow-up analysis include calorie calculator and body fat calculator.
Most bad outputs come from a few repeated input errors or interpretation mistakes. Use this short checklist before relying on the result.
- Treating BMI as a direct measurement of body fat.
- Comparing values without using the same unit assumptions every time.
- Ignoring waist, muscle mass, and medical context when interpreting the result.
