Millimeters to Inches Converter

Convert between meters, feet, inches, miles, and more.

Millimeters to Inches Conversion

Converting millimeters (mm) to inches is crucial in engineering, manufacturing, and design, especially when dealing with precision parts, screws, or screen bezels.

Calculation Formula

There are exactly 25.4 millimeters in one inch. To convert mm to inches, divide the millimeter value by 25.4.

Formula: Inches = Millimeters / 25.4

Standard Conversions

  • 1 mm = 0.039 inches
  • 5 mm = 0.197 inches
  • 10 mm = 0.39 inches
  • 20 mm = 0.79 inches
  • 25.4 mm = 1 inch
  • 50 mm = 1.97 inches
  • 100 mm = 3.94 inches

Engineering Precision

Engineering: Specifications often mix metric and imperial units. Converting mm to decimal inches is common for PCB design, mechanical parts, and architectural details.

In machining, "thou" (bits of an inch) are often used. 1 mm is approximately 39.37 thou (thousandths of an inch).

Other Applications

Rainfall: Weather reports may measure rain in mm or inches depending on the region.

Paper Sizes: A4 paper is 210mm wide, which converts to approximately 8.27 inches.

Why use decimals?

Inches are traditionally divided into fractions (1/16, 1/32), but digital converters usually output decimal inches (e.g., 0.5 instead of 1/2) for greater precision and easier calculation.

FAQ

What is 10mm in inches?
10mm is distinctively close to roughly 2/5 of an inch, or 0.39 inches.

How many mm in a 1/2 inch?
A half inch is equal to 12.7 mm.