BMI Calculator
Calculate Body Mass Index in metric (kg/cm) or imperial (lb/ft/in) — shows category and reference chart.
How to use this tool
- 1Click 'Metric (kg/cm)' or 'Imperial (lb/ft)' to choose the unit system.
- 2Enter your weight and height in the fields provided.
- 3Your BMI and category appear instantly in the result card.
About BMI Calculator
Body Mass Index is calculated as weight in kilograms divided by height in meters squared (kg/m²). For imperial units, the formula is (weight in pounds / (height in inches)²) × 703. This calculator supports both with a toggle: Metric mode takes weight in kg and height in cm (converted to meters internally); Imperial mode takes weight in lb and height in feet and inches (converted to total inches). The BMI value is shown to one decimal place in a large display, with the category colour-coded: Underweight (< 18.5, blue), Normal weight (18.5-24.9, green), Overweight (25-29.9, amber), Obese (≥ 30, red). A reference chart below shows all four ranges. Note that BMI is a screening tool only and does not account for muscle mass, age, sex, or body composition.
Frequently asked questions
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