# The Basics: Metric System

Conversion of units requires the use of a “conversion factor,” which is any equivalent equation in which the known and the unknown units are involved (Tables 3.1–3.4) (Bill 2000). You must set up a proportion of values on either side of the equation.

Cross-multiply and divide.

50 pounds = 22.7 kg

Unit | Fraction | Symbol |

Kilogram | 1000 grams | kg |

Gram | 1000 milligrams | g |

Milligram | 1/1000 of a gram | mg |

Microgram | 1/1,000,000 of a gram | μcg or μg |

**Table 3.2.** Weight.

**Table 3.3.** Volume.

1 kilogram | = | 2.2 pounds |

1 teaspoon | = | 5 mL |

1 tablespoon | = | 15 mL |

1 grain | = | 60 mg |

# Percentages

Percent can be expressed as “out of 100” or “for every 100.” For example: 25% can be written as

The decimal point can be moved two places to the left to achieve the same calculation.

*Agent strength as percent solution*

Agents with the dose listed as a concentration percent represent grams in 100 mL.

**Lasix** as a 5% solution has a concentration of 50 mg/mL.

**Lidocaine** as a 2% solution has a concentration of 20 mg/mL.

The decimal point can be moved one place to the right in any percent solution to discern the mg/mL concentration.