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Inches to Centimeters Calculator | Convert Inches to CM Instantly

Convert inches to centimeters instantly. 1 inch = 2.54 cm exactly. Free calculator with conversion chart for measurements, crafts, and international sizing.

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Purpose

Converting inches to centimeters? This calculator helps you switch from imperial to metric measurements instantly. Perfect for international shipping, clothing sizes, DIY projects, or understanding product dimensions listed in different units.

The Exact Conversion: 1 inch equals exactly 2.54 centimeters. This isn't an approximation—it's the precise definition established by international agreement in 1959.

Whether you're ordering furniture from overseas, following a European recipe, or converting American measurements for a science project, this tool gives you accurate results every time.

How to use

How to Convert Inches to Centimeters

  1. Enter your measurement in inches using the input field above
  2. View your result instantly converted to centimeters
  3. Use the value for your international measurements

Quick Reference Chart

Inches Centimeters Common Use
1 inch 2.54 cm Base unit
6 inches 15.24 cm Phone screen
12 inches 30.48 cm 1 foot / ruler
36 inches 91.44 cm 1 yard
60 inches 152.4 cm 5 feet
72 inches 182.88 cm 6 feet

Quick Tip: For fast mental math, multiply inches by 2.5 for a rough estimate. For more precision, multiply by 2.54.

Examples

Practical Conversion Examples

Example 1: Standard Ruler (12 inches)

Converting a 12-inch ruler to metric:

12 inches × 2.54 = 30.48 cm

A standard foot-long ruler is about 30.5 cm.

Example 2: Laptop Screen (15.6 inches)

A laptop advertised with a 15.6-inch display:

15.6 inches × 2.54 = 39.62 cm

The diagonal screen measurement is approximately 40 cm.

Example 3: Photo Print (8 × 10 inches)

Converting a standard photo size:

Width: 8 inches × 2.54 = 20.32 cm
Height: 10 inches × 2.54 = 25.40 cm

An 8×10 photo is about 20×25 cm.

Example 4: Waist Size (32 inches)

Converting US pant waist size:

32 inches × 2.54 = 81.28 cm

A 32-inch waist equals approximately 81 cm in European sizing.

How it works

The Conversion Formula

Centimeters = Inches × 2.54

This formula is exact, not an approximation.

The History Behind 2.54

In 1959, the United States, United Kingdom, Canada, Australia, New Zealand, and South Africa agreed to define the international inch as exactly 25.4 millimeters (2.54 centimeters). This standardization ended slight variations between countries.

Why 2.54?

The inch was historically based on the width of a human thumb, which varied. The 2.54 cm definition was chosen because it was very close to existing standards while providing a clean decimal relationship.

Manual Calculation

To convert 5.5 inches to centimeters:

5.5 inches × 2.54 = 13.97 cm

FAQ

How do I convert inches to centimeters?

Multiply your inch value by 2.54 to get centimeters. For example, 10 inches × 2.54 = 25.4 cm. This conversion is exact because the inch is internationally defined as exactly 2.54 centimeters.

How many cm is 1 inch exactly?

One inch equals exactly 2.54 centimeters. This is not an approximation—it's the precise international definition established in 1959. This makes the inch-to-centimeter conversion one of the few that's mathematically exact.

How do I convert feet and inches to centimeters?

First convert feet to inches (multiply feet by 12), then add any remaining inches. Finally, multiply the total inches by 2.54. For example, 5 feet 8 inches = (5 × 12) + 8 = 68 inches. Then: 68 × 2.54 = 172.72 cm.

What is 6 inches in cm?

6 inches equals exactly 15.24 centimeters (6 × 2.54 = 15.24). This is roughly the length of a dollar bill or the diagonal of many smartphone screens.

Why is the conversion factor exactly 2.54?

In 1959, six countries (US, UK, Canada, Australia, New Zealand, and South Africa) agreed to define the international inch as exactly 25.4 millimeters. This created the exact conversion factor of 2.54 cm per inch, standardizing measurements across nations.

What's the difference between US and UK inches?

Since 1959, there has been no difference. Before that, US and UK inches varied slightly. The international inch agreement standardized the inch at exactly 2.54 cm worldwide, eliminating any discrepancy between countries.