421 mm to inches conversion

Millimeters (mm)

mm

Inches (in)

in

Result

0 inches

Common Conversions

1 mm

0.0394 in

10 mm

0.3937 in

25.4 mm

1 in

100 mm

3.937 in

About Millimeters and Inches

Millimeters (mm) and inches (in) are units of length measurement used in different systems:

Millimeter: A metric unit equal to one-thousandth of a meter.
Inch: An imperial and US customary unit of length, equal to 25.4 millimeters.

Conversion Formula

To convert millimeters to inches:

Inches = Millimeters ÷ 25.4

To convert inches to millimeters:

Millimeters = Inches × 25.4

Common Uses

Millimeters are commonly used in:

Technical drawings
Engineering
Scientific measurements
European manufacturing

Inches are commonly used in:

Construction (US)
Woodworking
Screen sizes
US manufacturing

How to Use This Converter

1

Enter Value

Type your measurement in millimeters in the input field.

2

Click Convert

Press the convert button or simply start typing - the result will update automatically.

3

Get Result

Your result will appear instantly. Use the copy button to copy the result.

4

Additional Features

Use the swap button to switch between mm to inches and inches to mm
Click reset to clear all values
Reference the conversion table below for common values

Detailed Results

Input Value

0 mm

Converted Value