What is 3 inches to millimeters? The answer is that 3 inches equals 76.2 millimeters.
How to convert 3 inches to mm? We know that one inch is equal to 25.4 millimeters, so to convert 3 inches to millimeters, we must multiply the amount of centimeters by 25.4, which means that 3 inches is equal to 3 inches × 25.4 = 76.2 mm.
See also: How to convert 3 mm to inches.