Nursing Math Academy · Module 3
Metric System & Conversions
Learn the units and decimal relationships used for medication doses, patient weight, fluid volume, and clinical measurements.Core idea: Metric conversions are based on powers of 10. Moving to a smaller unit makes the number larger; moving to a larger unit makes the number smaller.
Lesson
The Metric System
Units used every shift for medication mass, fluid volume, body weight, and measurement.
gram
Base unit commonly used for medication mass.
milligram
1 g = 1,000 mg
microgram
1 mg = 1,000 mcg
kilogram
1 kg = 1,000 g; used for body weight.
liter
Base unit for fluid volume.
milliliter
1 L = 1,000 mL.
centimeter
1 m = 100 cm.
millimeter
1 cm = 10 mm.
degrees Celsius
Metric temperature scale used in clinical care.
Metric Prefix Ladder
| Conversion | Relationship | Clinical example |
|---|---|---|
| kg to g | Multiply by 1,000 | 2 kg = 2,000 g |
| g to mg | Multiply by 1,000 | 0.5 g = 500 mg |
| mg to mcg | Multiply by 1,000 | 0.25 mg = 250 mcg |
| L to mL | Multiply by 1,000 | 1.5 L = 1,500 mL |
| mg to g | Divide by 1,000 | 750 mg = 0.75 g |
| mL to L | Divide by 1,000 | 250 mL = 0.25 L |
Medication-safety notation: Use mcg rather than the Greek symbol µg, and mL rather than cc. Always write a leading zero for values less than 1 (0.5 mg) and never write a trailing zero (5.0 mg).
Educational use only. Not a substitute for institutional policy or clinical judgment.