The simplest way to convert within the metric system is with decimal moves. There are several subunits of deci, hepta, centi, etc that represent each next size unit of measure within the metric system.  However, the only sub-units used in Pharmacology will represent three steps to the left or right for each sub-unit.  MEMORIZE THE FOLLOWING CHART and simply move the decimal to the right or left depending on the direction you are converting.

kilo

gram  liter  meter  unit

milli

micro

EXAMPLES:  Using the above chart, to convert from kilograms to grams it is a three-step decimal move to the right.  Likewise to convert from grams to kilograms would be a three-step decimal move to the left.  To convert from grams to milligrams, it would be a three-step move of decimal to the right.  To convert from milligrams to micrograms would be a three-step decimal move to the right.  To convert from micrograms to grams it would be a six-step decimal move to the left---three steps to get to milli and three more steps to get to grams.

This principle applies with other units of measurement within the metric system.  For example, to convert from milliliters (mL) to liters, it would be a three step move to the left.  To convert from units to milliunits, it would be a three step decimal move to the right.


Example problem #1:   50 g  =  _______ mg

Since milligram is on the right side of gram in the chart, that would be a three step decimal move to the right to go from grams to milligrams.

50 g  = 50000 mg


Example problem # 2:   675 mL  =  ______ L

Milliliters is on the right side of gram but you need to go back to the left to get to liter; therefore, this would be a three step decimal move to the left.


675 mL  =  O.675 L  

Leave the answer as calculated here and do not round.  Don't forget the "0" in front of the decimal.


Example problem #3:  5600 mg  =  _______ kg

Milligrams is on the right side of kilogram; therefore, moving from milligram to kilogram is a move to the left.  It would be a three-step decimal move to go from milligram to gram and then an additional three-step decimal move to get to kilogram for a total of 6 decimal moves.


5600 mg  =  0.005600 kg with decimal move.  Then drop the trailing zeros to give a final answer of 0.0056 kg.