Inches to MM Calculator
Converting inches to millimeters is a common need when ordering metric conduit fittings, working with international equipment specifications, or documenting measurements in metric units. While US electrical work uses imperial measurements, the global supply chain increasingly requires metric conversions for compatibility.
This calculator multiplies your inch value by 25.4 to give the exact millimeter equivalent. Enter any measurement in inches, including decimals, and get a precise metric result suitable for ordering parts, verifying specifications, or completing metric documentation.
Inches to MM Formula
Millimeters = Inches × 25.4
1 inch = exactly 25.4 mm (international standard)
The conversion factor of 25.4 is exact by definition. Common trade sizes convert cleanly: 1/2 inch equals 12.7 mm, 3/4 inch equals 19.05 mm, and 1 inch equals 25.4 mm. These values are useful when cross-referencing imperial conduit sizes with metric catalogs.
Frequently Asked Questions
How do you convert inches to millimeters?
Multiply the inch value by 25.4 to get millimeters. For example, 2 inches multiplied by 25.4 equals 50.8 millimeters. The conversion factor of 25.4 is exact by international definition.
How many millimeters is 1 inch?
One inch equals exactly 25.4 millimeters. This is an exact value, not an approximation, because the international inch is defined as precisely 25.4 mm.
When do electricians need to convert inches to millimeters?
Electricians convert inches to millimeters when ordering metric fittings, working with metric conduit systems, referencing international product catalogs, or documenting measurements for projects that require metric specifications.