Convert Inches to Millimeters

Convert Inches (in) to Millimeters (mm) instantly and accurately.

Inches (in)
Millimeters (mm)

Conversion Formula

mm = in × 25.4

About Inches

The inch (in) is a unit of length primarily used in the United States, Canada, and the United Kingdom. Historically, an inch was defined as the width of a man's thumb, but today it's precisely defined as 2.54 centimeters. Common examples include: a quarter coin is about 1 inch in diameter, a standard smartphone is roughly 6 inches tall, and most computer screens are measured diagonally in inches. The inch is divided into fractions like 1/2, 1/4, 1/8, and 1/16 for precision measurements.

About Millimeters

A millimeter (mm) is one thousandth of a meter, making it the smallest unit commonly used in everyday measurements. To visualize this, a credit card is about 1 mm thick, and a paperclip wire is roughly 1 mm in diameter. Millimeters are essential in engineering, manufacturing, and medicine for precise measurements. Rainfall is measured in millimeters, with 1 mm representing a very light drizzle. Most rulers and measuring tapes include millimeter markings for accuracy.

Quick Reference Table

Inches (in)Millimeters (mm)
1 in25.4 mm
2 in50.8 mm
5 in127 mm
10 in254 mm
25 in635 mm
50 in1270 mm
100 in2540 mm

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