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]
- WisTech Open. (2024, August 9). Nursing dosage calculations - Basic conversions [Video]. YouTube. CC BY 4.0. https://www.youtube.com/watch?v=K0z5xHowr5Y ↵
Base unit for volume in the metric system.
Base unit for mass in the metric system.
Base unit for length in the metric system.