Pharmacy Unit Converter
Convert between mg, mcg, g, mL, L, kg, lb, mmol, and other common pharmacy units.
Convert between common pharmacy units for mass, volume, and concentration.
Formula
mcg × 1000 = ng mg × 1000 = mcg g × 1000 = mg kg × 1000 = g
Always check the units on the prescription, vial, and pump together to avoid 1000-fold errors.
Step-by-step method
- 1
Identify the source and target unit
Read the unit on the prescription and the unit you need to convert to (e.g. mg → mcg).
- 2
Use a metric ladder
Each step (kg ↔ g ↔ mg ↔ mcg ↔ ng) is a factor of 1000. Move down the ladder → multiply by 1000; move up → divide by 1000.
- 3
Watch the decimal point
Misplacing a decimal is the most common cause of 10-, 100-, or 1000-fold dosing errors. Write the conversion explicitly.
- 4
Double-check with a colleague
For high-risk drugs (insulin, opioids, chemotherapy) ask another pharmacist or nurse to independently verify the conversion.
Worked example
Scenario: Convert 0.5 mg to mcg.
Answer: 0.5 × 1000 = 500 mcg.
Practice calculations for the CRA
500+ exam-style calculation questions with detailed explanations, mapped to the GPhC Common Registration Assessment Part 1.