CALCULATE • VISUALIZE • COMPARE

BMI Calculator

Calculate your Body Mass Index instantly. Visual BMI gauge, healthy weight range, ideal weight from 4 formulas, and save/compare calculations.

monitor_weightWeight

heightHeight

assessmentYour BMI Result

24.2

Normal weight

arrow_drop_up

UnderweightNormalOverweightObese

Healthy weight range for your height (170 cm)

53.5 - 72 kg

balanceIdeal Weight Formulas

Devine Formula

male65.9 kg

female61.4 kg

Robinson Formula

male65.2 kg

female60.8 kg

Miller Formula

male66 kg

female62.5 kg

Hamwi Formula

male66.7 kg

female60.7 kg

table_chartBMI Categories

BMI Range	Category
< 16.0	Severe Thinness
16.0 - 16.9	Moderate Thinness
17.0 - 18.4	Mild Thinness
18.5 - 24.9	Normal
25.0 - 29.9	Overweight
30.0 - 34.9	Obese Class I
35.0 - 39.9	Obese Class II
> 40.0	Obese Class III

How It Works

straighten

Enter your weight and height

calculate

BMI is calculated in real time

assessment

See your result on the visual gauge

bookmark

Save and compare multiple calculations

Understanding BMI

info

What Is BMI?

Body Mass Index (BMI) is a simple measure of body fat based on height and weight. The formula is weight (kg) divided by height (m) squared. It is used as a screening tool but does not measure body fat directly.

warning

Limitations

BMI does not distinguish between muscle and fat mass. Athletes may have a high BMI due to muscle. It also does not account for age, sex, bone density, or fat distribution. Use it as a general guide, not a diagnosis.

favorite

Ideal Weight Formulas

Four widely-used formulas estimate ideal body weight: Devine (1974), Robinson (1983), Miller (1983), and Hamwi (1964). Each uses height as the primary variable. Results vary because each formula was developed from different population studies.

Frequently Asked Questions

How is BMI calculated?expand_more

BMI is calculated by dividing your weight in kilograms by your height in meters squared (BMI = kg/m²). For imperial units, the formula is (weight in pounds × 703) ÷ (height in inches)². The result is a number that indicates whether you are underweight, normal weight, overweight, or obese.

What is a healthy BMI range?expand_more

A BMI between 18.5 and 24.9 is considered normal weight by the World Health Organization (WHO). Below 18.5 is underweight, 25-29.9 is overweight, and 30 or above is obese. These ranges apply to adults aged 20 and older.

Is BMI accurate for athletes?expand_more

BMI can be misleading for athletes and muscular individuals because it does not differentiate between muscle mass and fat mass. A muscular person may have a high BMI but low body fat. For athletes, body fat percentage or waist-to-hip ratio may be more accurate indicators.

What are the ideal weight formulas?expand_more

This tool uses four formulas: Devine (1974), Robinson (1983), Miller (1983), and Hamwi (1964). All calculate ideal weight based on height, with separate formulas for males and females. They were developed from clinical data and provide a range of estimates rather than a single number.

Does BMI apply to children?expand_more

BMI for children and teens (ages 2-20) is interpreted differently using age- and sex-specific percentiles called BMI-for-age. This calculator is designed for adults. For children, consult a pediatrician or use a CDC BMI percentile calculator.

Is my data stored anywhere?expand_more

No. All calculations are performed in your browser. No data is sent to any server. The "Save" feature stores results in memory only for the current session -- they are lost when you close or refresh the page.