The medium-sized line at the halfway point between each numbered centimeter measurement represents half a centimeter, or 5 millimeters. [2] X Research source This same labeling scheme is also used on longer metric measuring tools, such as meter sticks and tape measures.
If you’re trying to find out how long your smartphone is in millimeters, you would arrange your ruler so that the “0” marking is even with one of the device’s horizontal edges. Not all rulers have “0”s printed on them. If the one you’re using doesn’t, it’s safe to assume that the end of the ruler to the left of the “1” indicates “0mm. ”
If the last full centimeter measurement reads 1, multiplying it by 10 would give you 10, since 1cm = 10mm.
If the object you’re measuring is 1. 5 centimeters, multiplying 1 times 10 gives you 10, and adding 5 gives you a total length of 15mm. If it’s easier for you, you can also measure one centimeter past the end of your object and then subtract the number of millimeters in between. 2 centimeters (20 millimeters) minus 5 millimeters equals 15mm.
The prefix “centi” means “hundred,” signifying that a centimeter is one hundredth of a meter. By the same token, “milli” mean “thousand,” so a millimeter is one thousandth of a meter.
Using the formula described above, 6. 25 inches is equal to 158. 75 millimeters. Translating inches to millimeters is a little tougher than making other conversions, since inches are imperial units and millimeters are metric. [9] X Research source
If you’re 5 feet tall, you would be 1,524 millimeters tall. That sounds a lot more impressive!
The same basic principle that makes it possible to convert inches and feet to millimeters also applies here. There are 12 inches in 1 foot, so 12 x 25. 4 = 304. 8; a yard has 3 feet, so 304. 8 x 3 = 914. 4, and so on. It’s well known that the field of play on an American football field is 100 yards. What many might not know is that this amounts to a whopping 91,440 millimeters. Imagine trying to measure that out with a ruler![12] X Research source
If you don’t have a credit card handy, stack 10 sheets of 8 1⁄2 in (22 cm) x 11 in (28 cm) printer paper on top of each other to get a layer that’s about 1 millimeter thick. This may be harder to work with than a single plastic card, though. A “mil” is a little-used imperial unit that corresponds to one thousandth of an inch, and is not to be confused with millimeters. [14] X Research source
For this method, you’ll essentially be adding up 1 millimeter at a time in order to find the one of the object’s given dimensions.
You’ll be drawing a number of lines quite close together, so use light pressure to make the line as thin as possible. Sharpening your pencil or using a pen with an ultra-fine point will help.
Make sure you count the spaces between the lines and not the lines themselves, since there will be 1 too many. To increase your precision a bit, count every 4 lines as 3 millimeters total. This will help make up the difference, since the card isn’t exactly 1mm thick.
