Inch to Millimeter Converter
Enter a value in inch and get the equivalent in millimeter instantly. The calculator uses the standard unit relationship and runs directly in your browser.
Inch → Millimeter
Formula
This conversion page is dedicated to the inch-to-millimeter direction so the unit relationship, reverse path and examples are easy to find. For scale-factor units, XpressCalculator converts through the domain base unit using internationally recognized unit definitions. Temperature scales use their standard offset-and-scale equations rather than a simple multiplier.
Worked example
Starting with 1 inch (in), the converter returns 25.4 millimeter (mm). For any other value, enter the number above and the browser recalculates the result immediately.
Quick conversion table
| Inch | Millimeter |
|---|---|
| 1 in | 25.4 mm |
| 5 in | 127 mm |
| 10 in | 254 mm |
| 25 in | 635 mm |
| 50 in | 1270 mm |
| 100 in | 2540 mm |
Helpful guide
Unit conversions are most reliable when the source value and unit are identified correctly. Do not confuse similarly named US customary and imperial units, and keep significant figures appropriate to the precision of the original measurement. For engineering, scientific, medical or safety-critical work, confirm the measurement standard required by your application.
Use sensible precision and verify critical decisions with an authoritative source or qualified professional.
Frequently asked questions
How do I convert inch to millimeter?
Multiply the inch value by 25.4 to get millimeter. This page performs the conversion instantly and shows the relationship clearly.
Is this inch to millimeter conversion exact?
The mathematical unit factor is applied directly. Displayed results may be rounded for readability, so retain more digits when high precision matters.
Can I reverse the conversion?
Yes. Use the linked millimeter to inch converter to reverse the direction without re-entering the formula manually.