Inches to Millimeters (mm) Converter
Punch in your inches, get millimeters back. That's it. No formulas to memorize, no rounding headaches. Handles decimals like 0.25 inch and 1.5 inches without breaking a sweat.
Why Inches to Millimeters Matters
Ever order a screw online and it shows up way too big? Yeah, that's the imperial-to-metric problem in action. Engineers, woodworkers, and 3D printer folks run into this daily. One inch is 25.4 mm — easy to remember. But try doing 1.3 inches in your head at the workbench. Gets old fast.
Common Inch to mm Conversions
The ones people look up the most: 0.25 inch = 6.35 mm. 0.5 inch = 12.7 mm. 0.75 inch = 19.05 mm. 1 inch = 25.4 mm. 1.5 inches = 38.1 mm. 2 inches = 50.8 mm. Bookmark this and stop Googling the same thing every other week.
Frequently Asked Questions
25.4 mm, exactly. Not approximate — that's the official international definition. So 2 inches = 50.8 mm, half an inch = 12.7 mm. Pretty straightforward math once you know the base number.
Multiply 0.25 by 25.4. You get 6.35 mm. Or just punch it into the converter above and skip the math entirely.
More often than you'd think. 3D printing, CNC machining, jewelry making, hardware specs — metric is the standard in manufacturing worldwide, but tons of parts from the US still list inches. That gap isn't going away.