BMI

Health & Fitness

BMI Calculator

Calculate adult body mass index from metric measurements, view the corresponding screening category, see a height-specific reference weight range, and export a clear PDF record.

Height (cm) Weight (kg)

Body mass index0

General adult category-

Reference weight range-

BMI screening scale

Where the result falls

Underweight
below 18.5Healthy range
18.5-24.9Overweight
25.0-29.9Obesity
30 or above

Category	BMI range	General interpretation
Underweight	< 18.5	Below the general adult reference range
Healthy range	18.5-24.9	Within the general adult reference range
Overweight	25.0-29.9	Above the general adult reference range
Obesity	30.0+	Higher screening category requiring individual context

Decision view

Adult BMI screening gauge

The calculated value is positioned against the four general adult reference intervals.

Underweight< 18.5Healthy range18.5–24.9Overweight25.0–29.9Obesity30+

General adult category: -

How to use BMI Calculator

Measure height without shoes and enter a recent body weight measured under consistent conditions.
Read the BMI value and general adult screening category together with the height-specific reference-weight interval.
Use the dedicated scale to see distance from category boundaries, not as a diagnosis or body-fat measurement.
Discuss clinically important results with a qualified professional, especially when pregnancy, growth, high muscularity, or illness affects interpretation.

Calculator guide

Understanding BMI Calculator

Body mass index relates weight to height and is widely used as an adult screening measure. It is not a diagnosis and should be interpreted with health history, body composition, and professional judgment.

BMI value Weight in kilograms divided by squared height in meters.

Screening category A general adult classification associated with the calculated value.

Reference range A height-specific weight interval corresponding to BMI 18.5 through 24.9.

Context Age, pregnancy, muscle mass, and clinical factors can change interpretation.

Calculation method

How the calculation works

BMI = weight in kilograms / (height in meters)^2. Convert height from centimeters to meters, square it, and divide weight in kilograms by that squared height. Reference weights reverse the formula at BMI 18.5 and 24.9.

Interpretation

What BMI can and cannot distinguish

BMI adjusts weight for height, making it useful for broad adult screening, but it does not identify what the weight is made of or where body fat is stored.

Useful signal A consistent, inexpensive index that can support population screening and longitudinal review.

Muscle versus fat Two people with the same BMI may have very different body composition.

Fat distribution BMI does not measure waist circumference or visceral-fat pattern.

Clinical context Health history, laboratory data, medication, mobility, and other measurements can change the meaning of the number.

Worked example

Reading a 175 cm and 72 kg result

The formula divides 72 kg by 1.75 metres squared. The resulting value is about 23.5 kg/m², within the general adult reference interval.

Height conversion 175 cm becomes 1.75 m before squaring.

Denominator 1.75 × 1.75 equals 3.0625 m².

BMI result 72 ÷ 3.0625 is approximately 23.5 kg/m².

The arithmetic is direct; the health interpretation still requires individual context.

Worked situations

Practical examples

Calculate BMI from a height of 175 cm and weight of 72 kg.
Review the general adult BMI category boundaries.
Compare a current measurement with a later measurement while keeping height unchanged.

Better inputs

Useful tips

Measure height without shoes and use a recent weight.
Track trends under similar measurement conditions.
Discuss unexpected or clinically important results with a qualified professional.

Before relying on the result

Limitations and common mistakes

BMI does not directly measure body fat or fat distribution.
Adult category boundaries are not intended for children and adolescents.
Athletes, older adults, and pregnant people may require different assessment methods.

Reference

Key terms

BMI: Body mass index, a height-adjusted weight screening measure.
kg/m2: Kilograms divided by meters squared, the BMI unit.
Screening: An initial indicator that may prompt further assessment.
Range: An interval used for general reference rather than diagnosis.

Important note

Calculated from the entered measurements using the displayed method. It is a general reference and does not replace diagnosis or individualized professional guidance.

Frequently asked questions

What is the BMI formula?

BMI equals weight in kilograms divided by height in meters squared.

Is BMI a diagnosis?

No. It is a screening measure and cannot diagnose a health condition or directly measure body fat.

Does the calculator apply to children?

No. Children and teens require age- and sex-specific growth-chart interpretation.

Why can muscular people have a high BMI?

BMI measures total weight relative to height and cannot distinguish muscle from body fat.