C1 → C2 Final Volume Calculator
Calculate the stock volume (V1) and diluent required to make a final total volume (V2) at a target concentration (C2) from a stock concentration (C1).
Calculator
Enter C1, C2, and the final total volume (V2). This calculates the required stock volume (V1) and the diluent to add (V2 − V1).
Educational use only. Always interpret results in clinical context and verify with local policies.
How It Works
This calculator uses the dilution equation C1 × V1 = C2 × V2. It represents conservation of solute: the amount of drug/solute before dilution equals the amount after dilution.
You enter C1 (stock concentration), C2 (target concentration), and V2 (final total volume). The calculator solves for V1 (stock volume), then calculates diluent as V2 − V1.
Formula
Worked Examples
Example 1: Stock 10 mg/mL → Target 1 mg/mL, Final volume 50 mL. What stock volume (V1) do you need?
V1 = (1 × 50) ÷ 10 = 5 mL
Diluent = 50 − 5 = 45 mL
Example 2: Stock 2% → Target 0.5%, Final volume 100 mL. What stock volume (V1) do you need?
Diluent = 100 − 25 = 75 mL
When This Is Used
- •Preparing a fixed final volume from a concentrated stock
- •Medication dilution checks for syringes, bags, or bottles
- •Pharmacy compounding and aseptic preparation workflows
Clinical safety note: Always confirm units, ensure you entered final total volume (V2) (not diluent volume), and follow product instructions and local policy. Use independent double-checks for high-risk medications.
Related Calculators
Frequently Asked Questions
Clinical reminder: Always follow local protocols and consult medication information sheets. These examples are for calculation practice only.
References & Further Reading
Credible sources commonly used in healthcare education for dilution and medication calculations.
International Standards
Australia Resources
Tip: If your answer looks wrong, it’s usually a unit mismatch or using diluent volume instead of final total volume (V2).