Lesson overview
Medication Dilution Calculations: C₁V₁ = C₂V₂
Ready when you are
Start with short teaching slides, then answer the lesson questions. Your progress stays on this browser.
Learning outcomes
What you will learn
- explain dilution in plain English
- tell medication amount, liquid volume and concentration apart
- distinguish ‘dilute to’ / ‘final volume’ wording from ‘dilute with’ / ‘add’, while recognising ‘make up to’ wording
- explain what C1, V1, C2 and V2 mean
- calculate any one missing C1V1 = C2V2 value when the other three are known
- recognise that C1 and C2 must use a compatible concentration basis rather than assuming every percent strength is interchangeable
- use a new concentration for a later mg → mL calculation
- recognise when a result does not make sense for an ordinary dilution
Clinical connection
Why this matters
A dilution error can start with something as simple as confusing the starting volume with the final total volume, or reading ‘make up to’ as ‘add’. Giving every number one clear job makes the equation much easier to use correctly.
Quick concept
How C₁V₁ = C₂V₂ works for medication dilution
In a simple dilution relationship, the amount of the same medicine or solute carried forward is unchanged while concentration and total volume change. Use compatible concentration units on both sides, and remember that V₂ is the final total volume, not automatically the amount of diluent added.
Formula
C₁ × V₁ = C₂ × V₂
Worked example
Educational example: 100 mg/mL stock is used to prepare a verified final concentration of 20 mg/mL in a verified final total volume of 50 mL.
V₁ = (20 × 50) ÷ 100 = 10 mL
Answer: 10 mL of the stated stock solution is required mathematically
C₁V₁ = C₂V₂ checks concentration-volume arithmetic only. It does not decide whether a medicine may be diluted, which diluent to use, compatibility, stability, concentration limits, route, aseptic process or administration instructions.
Lesson plan
How the lesson works
- 1
Learn
Short teaching slides explain one idea at a time with plain-language examples.
- 2
Practise
Answer calculation or scenario questions and receive immediate feedback.
- 3
Finish
Complete the lesson check and save your learning progress on this browser.
Keep going
Learn, practise, apply and check this skill
Use the page that matches what you need next. Each resource has a different job, so the lesson can stay focused on teaching the skill.
Practise
Medication dilution practice questions
Practise C₁V₁ = C₂V₂, final-volume wording and concentration checks across four levels.
Understand
C₁V₁ = C₂V₂ explained
Review why the equation works, what each value means and the dilute-to versus dilute-with distinction.
Check
Medication Dilution Calculator
Solve for one missing verified concentration or volume value in C₁V₁ = C₂V₂.
Apply
Medication & IV Safety cases
Use preparation and concentration arithmetic inside realistic medication scenarios.