Inches to Millimeters Converter
Convert inches to millimeters. Free inches to mm calculator for precision engineering and manufacturing.Updated 2026-03-15
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Formula: mm = inches × 25.4
Common Inches to Millimeters Conversions
| Inches (in) | Millimeters (mm) |
|---|---|
| 0.25 in | 6.35 mm |
| 0.5 in | 12.7 mm |
| 0.75 in | 19.05 mm |
| 1 in | 25.4 mm |
| 1.25 in | 31.75 mm |
| 1.5 in | 38.1 mm |
| 2 in | 50.8 mm |
| 2.5 in | 63.5 mm |
| 3 in | 76.2 mm |
| 4 in | 101.6 mm |
| 5 in | 127 mm |
| 6 in | 152.4 mm |
| 8 in | 203.2 mm |
| 10 in | 254 mm |
| 12 in | 304.8 mm |
| 18 in | 457.2 mm |
| 24 in | 609.6 mm |
| 36 in | 914.4 mm |
How to Convert Inches to Millimeters
To convert inches to millimeters, use the formula: mm = inches × 25.4
For example, to convert 1 in to mm: 1 in = 25.4 mm
💡 This calculator does the conversion instantly as you type. All calculations happen locally in your browser — no data is sent anywhere.
Frequently Asked Questions
How many millimeters in an inch?
1 inch equals exactly 25.4 millimeters.
How do I convert fractional inches to mm?
Convert the fraction to decimal first, then multiply by 25.4. For example, 3/8 inch = 0.375 × 25.4 = 9.525 mm.
Cite this tool:
"Inches to Millimeters Converter." ConvKit, conv-kit.com, https://conv-kit.com/tools/inches-to-mm/. Accessed 2026-03-15.