One inch is equal to 25.4 millimeters: 1in = 25.4mm/in × 1in = 25.4mm. Multiply 10 inches by 25.4 to get millimeters: 10in = 25.4mm/in × 10in = 254mm. mm to inches . Inches to millimeters (mm) converter and how to convert. Convert inches to millimeters (in to mm) with the length conversion calculator, and learn the inch to millimeter formula. How do you convert inches to millimeters? To convert inches to mm you need to multiply the value in mm by 25.4 as there are this many millimeters in an inch. For example, suppose you have a length of 100 inches and you want to convert it to millimeters: multiply 100 by 25.4 which gives you 2,540mm. Learn how to convert 1 inch to millimeters with exact results, decimal places, fractions, and scientific notation. See the conversion table for 1 inch to mm and other lengths.
