Why is 1 inch exactly 2.54 centimeters?

In 1959, the international yard and pound agreement fixed 1 inch as exactly 2.54 cm to align imperial and metric systems.

What measurement standards use inches?

Screen sizes, clothing measurements, and tools are commonly measured in inches in the US, UK, and Canada. Most other countries use centimeters.

I'm buying a 65-inch TV — how wide will it actually be on my wall?

A 65-inch TV has a diagonal of 165.1 cm, but the width depends on aspect ratio. For a standard 16:9 screen, the width is about 143 cm (56.5 inches) and height about 80 cm (31.6 inches). Make sure to check the manufacturer's exact dimensions before mounting.

My jeans are labeled 32 inches in the waist — what is that in centimeters for a European size chart?

32 inches × 2.54 = 81.28 cm, so you'd round to 81 cm on a European waist chart. Most European sizing starts from the centimeter measurement, so 81–82 cm typically corresponds to a European size 42 in men's trousers.

Inches to Centimeters Converter

Enter a value to instantly convert between length units.

From

Precision4 dp

1 Inch = 2.54 Centimeter

Key Formulas

Centimeter → Inch

in = cm × 0.393701

Kilometer → Mile

mi = km × 0.621371

Foot → Meter

m = ft × 0.3048

Inch → Centimeter

cm = in × 2.54

Formula

cm = in × 2.54

Inches are standard in the US, UK, and Canada for measurements like screen diagonals and clothing. Centimeters are the global standard for precision work. European furniture stores list dimensions in centimeters, US stores in inches — when you're trying to fit a sofa or monitor bought online into a specific space, you need this quickly.

Source: NIST SP 811, Table B.8

Frequently Asked Questions

Real-World Examples

1 inch is the exact definition, 2.54 centimeters since 1959

1 in = 2.54 cm

A 27-inch monitor is 68.6 cm diagonally

27 in = 68.58 cm

A smartphone typically measures 5-6 inches or 13-15 cm diagonally

2 in = 5.08 cm

A standard 12-inch ruler is exactly 30.48 cm — handy to know when buying a replacement ruler abroad that lists its length in centimeters

12 in = 30.48 cm

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Inches to Centimeters Converter

Key Formulas

Formula

Frequently Asked Questions

Real-World Examples

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