Basic Conversions

Introduction to Basic Metric Conversions

Vocabulary:

Liter (L) – Base unit for volume in the metric system

Gram (g) – Base unit for mass in the metric system

Meter (m) – Base unit for length in the metric system


Metric System Conversions: 

Understanding how to convert within the metric system and between metric and standard (Imperial) systems is crucial for nurses. The metric system is widely used in health care. It’s based on powers of 10, making conversions straightforward, simple, and precise.

1. Learn the Metric Prefixes

Familiarize yourself with these common metric prefixes:

  • Kilo (k) = 1,000 times larger than base
  • Hecto (h) = 100 times larger than base
  • Deka (da) = 10 times larger than base
  • Base unit (e.g., meter, liter, gram)
  • Deci (d) = 10 times smaller than base
  • Centi (c)= 100 times smaller than base
  • Milli (m) = 1,000 times smaller than base
    • Use the mnemonic “King Henry Died Until Drinking Chocolate Milk” to remember these prefixes.

2. Dimensional Analysis Review

Rule 1. Set up the problem. What units will your answer have?

[latex]\frac{unit}{1} -or- \frac{unit}{unit}[/latex]

Rule 2. Work the problem until the unit(s) on one side match the units on the other.

Rule 3. Do your units MATCH?

Rule 4. Solve by multiplying all the top numbers and write the answer in the numerator, and then multiply all the bottom numbers and write the answer in the denominator.

[latex]\dfrac{numerator}{denominator}[/latex] = Dive the top by the bottom

Rule 5. Write the number to four (4) decimals and then round and write your units appropriately.

3. Conversion Steps

Nurses often convert between milliliters (mL) and liters (L) when administering medications or fluids.

Converting large units to small units

When going from larger to smaller units, multiply by 10 successively.

Converting small units to large units

When going from smaller to larger units, divide by 10 successively.

Converting between metric and standard (Imperial) systems

Examples of some conversions include:

    • 1 fluid ounce (oz) = 30 mL (approximately)
    • 1 pound (lb) = 16 ounces (oz)
    • 1 cup = 8 fluid ounces (oz)
    • 1 pint (pt) = 2 cups
    • 1 quart (qt) = 4 cups
    • 1 gallon (gal) = 4 quarts

Conversion Examples

(Large units to small units)

Convert 2 liters (L) to milliliters (mL) using dimensional analysis:

mL → 1000 mL / 1 L x 2 L = 2000 mL

 

(Small units to large units)

Convert 800 milliliters (mL) to liters (L) using dimensional analysis:

L → 1 L / 1000 mL x 800 mL = 0.8 L

 

(Metric system to standard/Imperial system)

Nurses often need to convert between metric and standard (Imperial) units. For example, if a patient consumed 20 ounces of fluid, and a nurse needed to record the total intake in milliliters (mL), they would perform the following conversion using dimensional analysis:

mL → 30 mL / 1 oz x 20 oz = 600 mL

 

Basic Metric Conversions to Memorize

 

1 cup (c) = 8 oz

 1 kg = 2.2 lbs

 1 mL = 1 cc

 1 teaspoon (t) = 5 mL

 1 Tablespoon (T) = 15 mL

 1 ounce (oz) = 30 mL

 Microdrip tubing = 60 gtt/mL

Basic Metric Conversion Tutorial[1]


  1. WisTech Open. (2024, August 9). Nursing dosage calculations - Basic conversions [Video]. YouTube. CC BY 4.0. https://www.youtube.com/watch?v=K0z5xHowr5Y
definition

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Nursing Dosage Calculations Copyright © 2024 by WisTech Open is licensed under a Creative Commons Attribution 4.0 International License, except where otherwise noted.