Calculate Body Mass Index (BMI) from height and weight with instant results and WHO health classification. Supports metric (cm/kg) and imperial (ft/lbs) units, shows BMI category color coding, and provides health guidance ranges. Essential for anyone tracking health metrics, fitness goals, or medical records.
Calculators
BMI Calculator
Enter values to see the result.
Calculate Body Mass Index (BMI) from height and weight with instant results and WHO health classification. Supports metric (cm/kg) and imperial (ft/lbs) units, shows BMI category color coding, and provides health guidance ranges. Essential for anyone tracking health metrics, fitness goals, or medical records.
Reviewed: 2026-09-18
Compute Body Mass Index from stature and mass, review the WHO classification band, and record the result — all processing stays in the browser.
Step 1
Choose Metric (cm/kg) or Imperial (ft/lbs). Imperial input is converted internally, so enter values exactly as measured.
Step 2
Provide stature and mass in the selected units. Use the optional reference-height buttons for a quick starting value.
Step 3
Enter age, sex, and waist circumference to enable the waist-to-height ratio and exercise recommendations.
Step 4
Press Calculate. The BMI value, WHO classification band with color coding, and healthy weight range appear in the result panel.
Step 5
Copy the numeric BMI value for a progress log, and compare successive measurements taken under the same conditions.
Consequence: Entering pounds where kilograms are expected produces a dangerously low BMI reading.
Fix: Check the unit selector. Use kg for metric, lbs for imperial. The tool converts automatically.
Consequence: Entering centimeters where inches are expected produces a very high BMI reading.
Fix: Verify the height unit matches your input. The tool supports both metric and imperial.
Consequence: Athletes may be classified as overweight despite having low body fat.
Fix: Use BMI as one indicator among many. Consider body fat percentage for a complete health picture.
Consequence: BMI measures weight-to-height ratio, not actual body fat. Two people with the same BMI can have very different body compositions.
Fix: Use BMI as a quick screening tool, not a definitive health assessment. Consult a healthcare provider for comprehensive evaluation.
Consequence: Entering centimeters in the feet/inches field or vice versa produces a wildly incorrect BMI.
Fix: Verify the unit selector matches your input method before calculating.
Record the BMI value and classification band at each session using identical units and measurement conditions, then compare successive entries to identify the direction of change.
When source measurements mix unit systems, convert them first so both values enter the calculator in the same system.
BMI = mass (kg) ÷ stature (m)² = 72 ÷ 1.75² = 23.5, which falls in the WHO Normal weight band (18.5–24.9). The result panel also shows the healthy weight range for 175 cm: 56.7–76.3 kg.
Enter your height and weight, select your unit system (metric or imperial), and the tool instantly calculates your BMI using the standard formula: weight (kg) / height (m)².
The WHO classifies BMI as: Underweight (below 18.5), Normal weight (18.5–24.9), Overweight (25–29.9), and Obese (30 and above). The tool color-codes your result accordingly.
BMI does not distinguish between muscle and fat. Athletes with high muscle mass may have a higher BMI despite being healthy. Consider using additional measurements like waist circumference.
No. All calculations happen locally in your browser. No height, weight, or BMI data is transmitted, stored, or logged anywhere.
A BMI between 18.5 and 24.9 is generally considered healthy. Below 18.5 is underweight, 25-29.9 is overweight, and 30+ is obese.
Yes, children and teens use age- and gender-specific BMI percentiles. This tool is designed for adults aged 20 and older.
The core BMI formula is age- and sex-independent for adults. Age and sex are used only for the optional guidance sections, since body-composition norms differ across demographic groups.
The range spans the WHO Normal band applied to your height: 18.5 × height² to 24.9 × height² in kilograms. It indicates the mass range that keeps BMI within the normal classification for the entered stature.
When waist circumference is provided, the tool computes waist ÷ height. A ratio below 0.5 is associated with lower central-adiposity health risk, complementing the BMI screening value.
Yes. After the initial page load, calculation runs entirely in the browser tab with no network access. Imperial-to-metric conversion, WHO classification, and the healthy-weight-range derivation all execute locally.
BMI Calculator performs all calculations locally in the browser. Stature, mass, age, and waist values are never uploaded, stored, or transmitted, and the page continues to function offline after the initial load.
