The Metric System of Measurements

The metric system of measurements is a decimalized system--meaning the units are related by powers of ten--for measuring various physical quantities, including length, mass and temperature. Most European countries use this system of measurement, while the United States uses a system based on older units. Fortunately, it is easy to convert measurements from one system to the other.

Common Metric Units

The metric system measures lengths and distances in terms of meters. Common units of length are meters, centimeters and millimeters, with a meter being equivalent to 100 centimeters or 1,000 millimeters. Distances are measured in terms of kilometers, which are equivalent to 1,000 meters.

Comparison to U.S. Measurements

A meter is slightly longer than a yard, which is equivalent to three feet in the U.S. system. A mile, which is 5,280 feet, is equivalent to approximately 1.6 kilometers.

Volume, Mass and Temperature

Volumes are measured in terms of liters; this unit is based upon cubic centimeters. A liter is slightly more than a quart in U.S. volume measurements. Mass is based upon the gram, which is equivalent to the mass of one milliliter of water.

Temperatures are generally measured using the Celsius scale (although the Kelvin scale is often used in scientific measurements), which sets the freezing point of water at zero degrees.

Use of the Metric System in the United States

The metric system is commonly used in chemistry classrooms, where students are required to measure volumes of liquids in liters or milliliters and weigh objects in grams or kilograms. Many beverage companies, particularly soda companies, print volume in liters on bottles and cans. Rulers also include centimeters, although this measurement is not commonly used in the U.S.

Conversion of Length and Mass from U.S. System to Metric System

To convert units from inches to centimeters, multiply by 2.5 centimeters/inch. Centimeters can then be converted to meters by multiplying the result by 100 centimeters/meter. Alternatively, you can multiply feet by .3 meter/foot to convert feet directly into meters.

Mass can be converted by multiplying pounds by 2.2 kilograms/pound; ounces can be multiplied by 28 grams/oz.