in

What is a Inch?

Length Unit

Definition

An inch is a unit of length equal to 2.54 centimeters or 1/12 of a foot. It is commonly used in the United States, Canada, and the United Kingdom.

History

The inch was historically defined as the width of a man's thumb or three barleycorns laid end to end. The modern inch was standardized internationally in 1959 as exactly 25.4 millimeters.

Common Uses

  • Screen sizes for TVs, monitors, and phones
  • Tire and wheel dimensions
  • Woodworking and construction
  • Rainfall measurements in the US

Fun Facts

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TV and monitor sizes are measured diagonally in inches

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The inch symbol (″) is called a double prime

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An inch of rain equals about 4.7 gallons per square yard

All Inch Conversions