Inches to Millimetres Converter

Convert in to mm instantly — 1 in = 25.4 mm. Free, browser-only tool.

Ad placeholder (leaderboard)
Enjoying the tools? Go Pro for £4.99 (one-time) and remove all ads — forever, on this device. Remove ads — £4.99

Inches to Millimetres Converter

This free length converter converts Inches (in) to Millimetres (mm) and back again. The exact conversion factor is 1 in = 25.4 mm, so 10 in equals 254 mm.

Type a value in either field — the result updates in real time. The reference table below shows common conversion values at a glance. All calculations run entirely in your browser with no data sent to any server.

Inches (in)Millimetres (mm)
1 in25.4 mm
5 in127 mm
10 in254 mm
100 in2540 mm
Ad placeholder (rectangle)