There are approximately 25.4 millimeters in an inch. To convert inches to millimeters, you can use this conversion factor. So, if you have a measurement in inches and want to express it in millimeters, you can multiply the measurement in inches by 25.4 to get the equivalent measurement in millimeters.
One inch is equal to 25.4 millimeters:
1in = 25.4mm/in × 1in = 25.4mm
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