Dilutions & Concentrations
Dilution and concentration calculators for C1V1, reconstitution, and mixing to a target strength (mg/mL) — with formulas and worked examples.
C1V1=C2V2 Basic
Standard dilution formula calculations
C1 to C2 Final Volume
Determine stock volume needed for target concentration
Desired Concentration to Volume
Calculate final volume for a target concentration
mg Powder to Concentration
Work out concentration after adding diluent to powder vial
Multi-Step Serial Dilution
Calculate final concentration after N serial dilutions
Paediatric Dilution
Calculate pediatric-strength solution from adult stock
Reconstitute to Bag
Final bag concentration after multi-step reconstitution
Serial 2-Step Dilution
Plan a 2-step serial dilution (stock → intermediate → final)
Stock Achieved Concentration
Calculate achieved concentration after mixing volumes
Vial Dose to mL
Convert prescribed dose to volume using vial concentration
How Dilution & Concentration Calculations Work
Dilution and concentration calculations determine how a medication's strength changes when volume is added, removed, or transferred. These calculations help ensure medications are prepared accurately for safe administration.
Dilution calculations are commonly required when reconstituting powdered medications, preparing IV bags or syringes, performing serial dilutions, or adjusting concentrations to a prescribed target. When checking units, ensure you're using the final volume after all mixing is complete, not just the diluent added.
Common Dilution & Concentration Calculations Explained
C1V1 = C2V2 (dilution equation)
Use C1V1 when you're changing volume and need a new concentration (or need to work out the volume required).
Example question:
You have a stock solution of 50 mg/mL. You need 10 mL of 10 mg/mL. How much stock (mL) is needed?
Worked example:
Answer: 2 mL of stock solution
Tip: Work out what you need (C2×V2), then divide by C1.
Reconstitution concentration (mg/mL)
Reconstitution converts a known amount of drug into a liquid concentration after a final volume is made up.
Example question:
A vial contains 1,000 mg of powder. After reconstitution, the final volume is 20 mL. What is the concentration in mg/mL?
Worked example:
Answer: 50 mg/mL
Tip: Use the FINAL volume after mixing.
Mixing to a target concentration (mg/mL)
Sometimes you have a known amount of drug and need to work out what final volume gives the target strength.
Example question:
You have 500 mg total drug and need a final concentration of 5 mg/mL. What final volume is required?
Worked example:
Answer: 100 mL final volume
Tip: Amount ÷ target strength = final volume.
When These Calculators Are Used
- •Preparing a target concentration (mg/mL) from a stock solution
- •Working out how much stock solution is needed (C1V1 problems)
- •Checking concentration after reconstitution or mixing
- •Planning multi-step dilution setups (stock → intermediate → final)
- •Double-checking math during medication preparation tasks
Clinical safety note: Always confirm units (mg, mL), the stated concentration, and local protocols when preparing dilutions. These calculators support calculation checking but do not replace professional judgement. Examples on this page are for calculation practice only.
Related Calculator Categories
Frequently Asked Questions
Clinical reminder: Always follow local protocols and consult medication information sheets. These examples are for calculation practice only.