Inches to Millimeters Converter

Summary

Type any value in inches and get the exact millimeter equivalent instantly, plus a handy reference table.

How it works

1. Enter a value in inches in the input field.
2. The equivalent in millimeters appears instantly below.
3. The formula used is: mm = inches × 25.4.
4. Scroll down to the reference table for common inch-to-mm conversions.
5. Click any row in the table to load that value into the converter.

Use cases

• Convert screen or monitor sizes (e.g. 27 inches) to millimeters.
• Convert US clothing or shoe measurements to metric sizes.
• Check furniture or room dimensions when switching between unit systems.
• Convert engineering or machining measurements from inches to mm.
• Verify product dimensions listed in inches when you need millimeters.
• Convert craft or sewing measurements to the metric system.
• Compare specifications between US and international products.
• Convert paper sizes (e.g. letter vs A4) between inch and mm values.

Frequently Asked Questions