⚖️ BMI Calculator

BMI (Body Mass Index) is a quick screening tool that estimates body fat using just height and weight. Enter your measurements into our free BMI calculator to get your BMI score, weight category, and healthy weight range instantly.

How it works: BMI = weight (kg) / height² (m²). For imperial: (weight in lbs × 703) / height² (in²). Our calculator handles both. A 5'10" (178cm) person weighing 175 lbs (79kg) has a BMI of 25.1 — at the boundary of normal and overweight.

BMI categories: Below 18.5 = underweight. 18.5-24.9 = healthy weight. 25-29.9 = overweight. 30+ = obese (Class I 30-34.9, Class II 35-39.9, Class III 40+). Your waist measurement adds context to BMI — men should be under 40", women under 35".

Limitations: BMI doesn't measure muscle vs fat, bone density, or fat distribution. Two people with the same BMI can have very different health profiles. Use our calculator as a starting point, then consult a doctor for a complete assessment.

Related: Pair your BMI reading with our Calorie Calculator to determine daily needs for weight loss or gain. Use the Age Calculator for health benchmarks by age group. The Unit Converter helps if you need metric/imperial conversions.

Regular BMI tracking helps spot trends before they become problems. A slow BMI increase of 0.5 per year might go unnoticed without tracking. Use our tool monthly and combine with waist circumference for a fuller health picture.