Height & Weight Converter + BMI Calculator

Convert global height and weight units, calculate BMI, and see your result with a simple visual guide.

  • ↔Unit Conversionkg, lb, cm, ft, and more
  • ✦BMI CalculationInstant adult reference
  • ♙Visual Body ShapeIllustrative silhouette
  • ◎Global-ready30-locale architecture

▣ BMI Calculator

Unit system

▥ Your Result

BMI22.5Normal weight
22.5
Underweight
< 18.5Normal
18.5 – 24.9Overweight
25.0 – 29.9Obesity
≥ 30.0

This is a general adult BMI reference.
It is not a medical diagnosis.

♙ Body Shape Simulation

170 cm(5′ 7″)
Illustrative body silhouette

BMI 22.5Normal weight

Your input
Height
170 cm
Weight
65 kg
BMI
22.5
Category
Normal weight

Illustrative visualization only — not a measurement of body composition.

▰ Weight Converter

1 lb = 0.45359237 kg   |   1 kg = 2.20462 lb

╱ Height Converter

1 in = 2.54 cm   |   1 ft = 30.48 cm   |   1 m = 100 cm

▤ What is BMI?

BMI (Body Mass Index) is a simple index that uses height and weight to place adults in broad reference categories.

Read the FAQ →

▣ How is BMI calculated?

BMI = weight (kg) / height (m)2

Your inputs are converted to metric units before the calculation.

See calculation details →

▥ Adult BMI reference

Underweight< 18.5
Normal weight18.5 – 24.9
Overweight25.0 – 29.9
Obesity≥ 30.0

How this tool works

Enter your height and weight in metric or US units. The calculator converts values with standard physical constants and calculates BMI as kilograms divided by meters squared. Displayed values are rounded only after the calculation.

BMI limitations

BMI does not directly measure body fat, muscle mass, bone density, or body composition. It is an educational adult reference and is not a diagnosis. Children, athletes, pregnant people, and people with particular health circumstances may need an assessment that uses other information.

? FAQ — Frequently Asked Questions

How do I convert pounds to kilograms?

Multiply pounds by 0.45359237. For example, 100 lb equals 45.36 kg. Use the weight converter above when you need to switch units in either direction.

How do I convert feet and inches to centimeters?

Convert feet to inches, add the remaining inches, then multiply by 2.54. Five feet ten inches equals 177.8 cm. The height converter accepts feet and a separate inches value.

Which height and weight units does this tool support?

The BMI calculator accepts centimeters and kilograms, or feet, inches, and pounds. The separate converters also support meters, grams, ounces, and direct unit swapping.

What formula does the BMI calculator use?

BMI equals weight in kilograms divided by height in meters squared: kg ÷ m². When you enter US units, this site converts them to metric units first and then applies the same formula.

Why does height have such a large effect on BMI?

Height is squared in the BMI formula. For the same body weight, a shorter height produces a higher BMI and a taller height produces a lower BMI, so enter your measurement as accurately as practical.

Is BMI a medical diagnosis?

No. BMI is a broad adult screening reference and does not diagnose health conditions. A clinician can consider medical history, symptoms, measurements, and other factors that BMI does not include.

Does BMI measure body fat or describe muscular people accurately?

No. It cannot separate muscle, fat, bone mass, or body composition. Athletes and people with unusually high or low muscle mass may find that BMI is less representative of their individual situation.

Can I use this calculator during pregnancy?

Standard adult BMI categories are not designed to assess pregnancy-related weight changes. For pregnancy-specific guidance, discuss measurements and weight goals with a qualified healthcare professional.

Can I use this calculator for children or teenagers?

This tool uses adult BMI reference categories. Children and teenagers require age- and sex-specific BMI-for-age assessments, so use an appropriate pediatric reference or seek professional guidance.

How accurate are the conversion and BMI results?

Unit conversions use standard fixed conversion factors, and BMI is rounded only after the calculation. The usefulness of the result still depends on accurate height and weight entries and on whether adult BMI is appropriate for the person being assessed.

Are my height and weight saved or sent anywhere?

No. Calculations run in your browser. This site does not send, store, or create an account from the height and weight values you enter.

How often should I check my BMI?

There is no single schedule that suits everyone. If you track BMI, measure under similar conditions and focus on changes over time alongside other health information rather than relying on one isolated number.