Inches to mm Converter
1 inch = 25.4 mm exactly. Used in engineering drawings, fastener sizing and screen dimensions.
Formula:1 in = 25.4 mm
⇄ Switch to Mm To InchesInch to Millimeter — common values
1 in25.4 mm
5 in127 mm
10 in254 mm
50 in1,270 mm
100 in2,540 mm
500 in12,700 mm
1,000 in25,400 mm
How to convert Inches To Mm
To convert inches to mm, use the formula: 1 in = 25.4 mm. Enter any value in the input field above and the result appears instantly. Click the ⇄ button or use the “Switch to Mm To Inches” link to reverse the conversion.
All conversions use precise mathematical constants validated against international SI standards (NIST and ISO 80000) and are accurate to 8 significant figures.
Frequently Asked Questions
What is the formula to convert Inches To Mm?
1 in = 25.4 mm. 1 inch = 25.4 mm exactly. Used in engineering drawings, fastener sizing and screen dimensions.
Is this converter free?
Yes — completely free, no registration required. Works instantly in your browser.
How do I convert Mm To Inches?
Use the Mm To Inches converter or click the ⇄ switch button above.
More Length conversions
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The full converter supports all unit combinations