BMI Calculator

Free BMI calculator supporting metric and imperial units. Instantly calculate your Body Mass Index, see your BMI category (underweight, normal, overweight, obese), view a visual BMI scale, get your healthy weight range, and track your BMI history over time.

Weight (kg)

Height (cm)

Enter your weight and height above to calculate your BMI in real time.

BMI Categories Explained

Underweight (BMI < 18.5)

May indicate malnutrition, an eating disorder, or other health conditions. Consult a healthcare professional.

Normal (BMI 18.5 - 24.9)

Generally considered a healthy weight range. Associated with the lowest health risks for most adults.

Overweight (BMI 25 - 29.9)

May increase risk of cardiovascular disease, type 2 diabetes, and other conditions. Lifestyle changes may help.

Obese (BMI >= 30)

Significantly increases risk of serious health conditions. Medical consultation is recommended.

Note: BMI is a screening tool, not a diagnostic measure. It does not account for muscle mass, bone density, age, sex, or ethnicity. Always consult a healthcare professional for a complete health assessment.

How to Use BMI Calculator

1Select metric (kg/cm) or imperial (lbs/ft+in) units.
2Enter your weight and height.
3View your BMI, category, visual scale, and healthy weight range.
4Click 'Copy Result' to save or share.

Frequently Asked Questions

What is BMI?▾

Body Mass Index (BMI) is a measure calculated from your height and weight. It's used as a screening tool to indicate whether you're underweight, normal weight, overweight, or obese.

How is BMI calculated?▾

BMI = weight (kg) / height (m)². For imperial units: BMI = (weight in lbs / height in inches²) × 703.

What is a healthy BMI range?▾

A BMI between 18.5 and 24.9 is considered normal weight. Under 18.5 is underweight, 25-29.9 is overweight, and 30+ is obese.

Is BMI accurate for everyone?▾

BMI is a screening tool, not a diagnostic measure. It doesn't account for muscle mass, bone density, age, sex, or ethnicity. Athletes may have a high BMI due to muscle. Always consult a healthcare professional.

About BMI Calculator

NexTool's BMI Calculator is completely free to use with no sign-up required. Your data is processed directly in your browser and never sent to our servers, ensuring complete privacy and instant results.