When it comes to measurements, the abbreviation "mm" typically stands for "millimeters." Find out how many mm in diameter equals one inch with help from a longtime mathematics educator in this free video clip.

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When it comes to measurements, the abbreviation "mm" typically stands for "millimeters." Find out how many mm in diameter equals one inch with help from a longtime mathematics educator in this free video clip.

Part of the Video Series: Math Instruction

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Hi, I'm Jimmy Chang, and we're here to talk about how many millimeters in diameter equals one inch. Now, diameter is kind of important, but what really matters is converting and talking about how many millimeters in one inch. Now, the one formula that you want to think about is actually this that folks tend to recognize more often than not. One inch is going to approximate 2.54 cm. We're talking about converting from English to metric units here. So, if 1 inch is approximately 2.54 cm, you want to think about how this relates to millimeters. Now, if you think about centimeters and millimeters, 1 cm is actually 10 mm. So, the idea here is, if you understand that fact, what you can do is take the 1 inch approximately equal to 2.54 cm, and then simply multiply this by 10. So, the idea here is, using this logic, you have 1 inch is approximately equal to 25.4 mm. You can multiply by 10. You could shift the decimal over one place, but either way, this will be what you're looking for. So, I'm Jimmy Chang, and that's how many millimeters equals 1 inch in diameter.