Why use Metrics?

The metric system was devised by French scientist in the late 18 th century to help organize the chaos of different units being used to measure. These scientists had two goals in mind. One was to create a system that was used by all and the other was to use decimals rather than fractions. Other than the United States, most of the rest of the world measures in metrics. As scientists, we have adopted the metric system for two main reasons.

First, it is universal. Scientists worldwide use the metric system in their work so that everyone can agree on measurements taken. By sticking to the metric system, it is easier to compare results without error in conversion.

Second, it is simple. The metric system uses one basic unit of measure in each category of measure. For example, all length is measured in meters. All measurements smaller or larger are converted using powers-of-ten multipliers. All basic units use the same prefixes to show a larger or smaller quantity.

The prefixes (meaning what comes in front of the basic unit) in the metric system are Latin based and mean the number they represent. For example, we know that a dozen is 12 of something. The same is true for metrics. A deca is always 10 of something, a kilo is 1000 of something, and so on. The metric system also replaces fractions with decimals which are much easier to convert.

Basic Units:

  • Length - meter
  • Volume - liter
  • Weight - gram
  • Temp - degrees Celsius


  • kilo = 1000
  • centi = 1/100
  • milli = 1/1000
  • several others



Biology Department NSF

When using this chart to convert metric measurements, remember: 

  • If you are measuring length use meters. 
  • If you are measuring dry weight use grams.
  • If you are measuring liquid capacity use liters.
  • To convert from a larger to smaller metric unit you always multiply.
  • To convert from a smaller to larger unit you always divide



When you move down the stairs you are multiplying by 10 for each step. So you are adding a zero to your original number and moving the decimal one place to the right with each step.

When you move up the stairs you are dividing by 10 for each step. You are then adding a zero in FRONT of your original number and placing the decimal one place to the left with each step.



STEP 1: Determine your starting unit and whether you need to go up or down the ladder.

STEP 2: Determine how many steps there are from your start to the unit you need to be at.

STEP3: Move the decimal the amount of places that was determined in steps 1 and 2.


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This material is based upon work supported by the National Science Foundation under Grant No. 0442049.

Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.