Inches to Millimeters converter

Convert inches (in) to millimeters (mm). Exact factor: 1 in = 25.4 mm.

Converter tool

Formula: mm = in × 25.4

Quick examples

InchesMillimeters
0.512.7
125.4
250.8
4101.6
6152.4
8203.2
10254.0
12304.8

How to convert Inches to Millimeters

Formula: mm = in × 25.4.

Reverse conversion: in = mm × 0.03937007874015748

Tip: Use the swap button to reverse the calculation instantly.

Inches → Millimeters FAQs

What is the exact conversion factor?

Inches × 25.400000000000 = Millimeters.

How do I go the other way?

in = mm × 0.03937007874015748

Are the results rounded?

Calculations use exact constants; values are displayed with sensible rounding for readability.