Appendix B - Using the Metric System

Metric Conversions

The metric system consists of standard measurements and prefixes that change these measurements by factors of 10. For example, the standard measurement of length is the meter. when we have 1000 meters it is called a kilometer. Below is a table of prefixes and there relationship to the standard (or base measurement).

It is much easier to write 1 kilometers then it is to write 1000 meters. You can also think of these as which direction to move the decimal. For example if you have 10 meters and you want to know 1) how many millimeters (mm) that is and 2) how many kilometers that is, you will start with the conversion.

1) 1 meter = 1000 millimeters. So to go from meters to mm you must move the decimal 3 places to the right (notice that milli is 10^-3). So 10 meters is the same as 10,000 mm. (you can achieve the same goal by taking 10 x 1000).

2) 1 kilometer = 1000 meters. So we must again move the decimal, but this time 3 places to the left (1 km = 10³ meters). Therefore 10 meters is the same as 0.010 km.

Another example. How many centimeters (cm) in 2.5 meters? Centi is 10^-2 meters (or 100 cm = 1 meter), so move the decimal 2 places to the right. 2.5 m = 250 cm

Click below to practice converting between types of metric units. Remember, these prefixes can be used in front of any of the standard measurements (liters, grams, etc.).

Metric Conversion Practice

English to Metric Conversion

The English system of measurement is not as easy. For example, there are 12 inches in 1 foot and 3 feet in 1 yard. The English system does not always convert by a consistent factor. Therefore, it is important to be able to convert between common English measurements and the metric system. The table below lists some common conversions. Practice converting between English and metric units.