Body Mass Index (BMI) is a measure of body weight relative to height. It is calculated as weight in kilograms divided by the square of height in meters, or as (weight in pounds × 703) ÷ height in inches squared.

How do I calculate my BMI?

Metric: BMI = weight (kg) ÷ height (m)². Imperial: BMI = (weight in lbs × 703) ÷ height (in)². Example: a person who is 175 cm and 70 kg has BMI 22.9 (normal weight).

What is a healthy BMI for adults?

According to the World Health Organization, a normal BMI for adults is 18.5 to 24.9. Below 18.5 is underweight, 25.0–29.9 is overweight, and 30.0 or above is obese.

What BMI is considered obese?

A BMI of 30.0 or higher is classified as obese by the WHO: Class I (30.0–34.9), Class II (35.0–39.9), and Class III (40.0 and above).

How do I calculate BMI for 175 cm and 70 kg?

Convert 175 cm to 1.75 m. BMI = 70 ÷ (1.75)² = 70 ÷ 3.0625 = 22.9. This falls in the normal weight range (18.5–24.9).

Is BMI accurate for athletes and muscular people?

BMI may overestimate body fat in muscular individuals because it does not distinguish muscle from fat. Athletes and people with high muscle mass should use additional measures such as body composition analysis.

Can I use this BMI calculator for children?

No. BMI for children and teens uses age- and sex-specific percentile charts. This calculator is intended for adults aged 18 and older.

Is BMI the same as body fat percentage?

No. BMI is a weight-for-height index. Body fat percentage directly measures fat mass. A muscular person can have a high BMI but low body fat.

Is there a free online BMI calculator?

This site offers a free, accurate BMI calculator supporting metric and imperial units with instant WHO category results. No account required.

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Last updated: 20 July 2026

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