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RMIT University Library - Learning Lab

Converting between large and small units


How do you convert between units? Nurses use units that begin with milli and micro a lot. If you express your dosage in a smaller unit, the number must get bigger, and vice versa.

Find out how to convert dosages between larger and smaller units.

If one day, you decide to keep a pet elephant, chances are you will only have room for one. If, on the other hand, you decided to have pet mice, the same space would accommodate probably thousands of them.

Therefore, when converting from a large unit to a small unit, you can have more of them. This means that the number increases, which means the decimal point will move right. In the example, one microgram which is the larger unit is being converted to mcg which is smaller, from milli to micro you will need to  move the decimal point three places, and that is three places to the right. On the other hand, one mouse only takes up a small part of an elephant.So if you're converting from a small unit to a large unit you will not have many... You’ll only have a small fraction.

In this example, we are changing three milligrams (which is now the smaller of the two units) to grams (which is the larger of the  two units). From milligrams to grams there is a factor of 1000, this mean moving the decimal point three places. The number gets smaller by a fraction of 1000 so it is now three places to the left.

So when going to a larger unit to a smaller unit—such as grams to milligrams—the number that you have will get larger and this means that the decimal point shifts to the right.

In contrast, If you are going to a smaller unit to a larger unit—such as microlitres to litres—the number that you have will get smaller and this means shifting the decimal point to the left. The end, thank you!