Inches

Inches Explained: Conversion Chart, Tools, and Real-World Examples

By MeasureBeam Editorial Team · · 3 min read
An inch is a unit of length equal to exactly 2.54 centimeters, 25.4 millimeters, or 1/12 of a foot. It is the standard small-measurement unit in the US imperial system, used for everything from screen sizes to shoe sizes.

What Is an Inch?

The inch is a unit of length in the US customary and imperial systems. Since 1959, it has been defined by international agreement as exactly 2.54 centimeters, not an approximation, the legal standard used worldwide.

You will see inches used for screens and hardware (TVs, laptops, bolts), body measurements (height, shoe size, ring size), and paper sizes in the US. Almost everywhere else, the equivalent everyday unit is the centimeter.

Inches Conversion Chart

Inches Centimeters Millimeters Feet
1 in 2.54 cm 25.4 mm 0.083 ft
6 in 15.24 cm 152.4 mm 0.5 ft
12 in 30.48 cm 304.8 mm 1 ft
24 in 60.96 cm 609.6 mm 2 ft
36 in 91.44 cm 914.4 mm 3 ft
60 in 152.4 cm 1524 mm 5 ft

Need a number that is not on this table? Use the full Inches to Centimeters Converter or the Inches to Feet Converter for an exact result on any value.

Converting Inches: Which Tool to Use

How Big Is an Inch, in Real Terms?

An inch is roughly the width of an adult thumb at the knuckle, or the diameter of a US quarter minus a couple of millimeters. It is a small enough unit that most everyday objects are described in multiples of it rather than single inches.

For a visual sense of specific sizes, see our breakdowns of things that are 24 inches long, things that are 36 inches (one yard), and things that are 60 inches tall (5 feet).

Common Inch Measurements You Will Run Into

  • TV and laptop screens are measured diagonally in inches (13 to 85 inches is the typical range)
  • Ring sizes are based on inner circumference in fractions of an inch
  • Shoe sizes roughly correspond to foot length in inches plus a fixed offset
  • Pizza sizes are measured by diameter in inches (small is usually 10, large 14 to 16)
  • Paper sizes in the US use inches (Letter is 8.5 x 11 inches)

Frequently Asked Questions

How many centimeters are in an inch?

Exactly 2.54 centimeters. This is the internationally agreed exact value, not a rounded figure.

How many inches are in a foot?

12 inches make up 1 foot. 36 inches make up 1 yard.

Why does the US still use inches instead of centimeters?

The US never fully converted to the metric system. Inches, feet, and miles remain the everyday standard, while science, medicine, and most manufacturing in the US already use metric internally.

What is a quick way to estimate inches to cm in my head?

Multiply by 2.5 as a fast estimate, then add roughly 2% for a closer number. For an exact figure, use the Inches to Centimeters Converter.

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