Known C1, V1, C2 or V2
Solve a dilution relationship
Use C1V1=C2V2 when the starting solution and intended dilution are already verified and one value is missing.
Open dilution calculatorDilution & Reconstitution Calculations
Choose the arithmetic task after the preparation values have been verified from the approved medicine or pharmacy source. MedMaths checks the maths; it does not create preparation instructions.
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Which preparation value are you trying to find?
Start with the preparation values that have already been verified. The cards separate dilution, final-concentration checking and simple vial dose withdrawal.
Verified transfer + final volume
Check final IV concentration
Use the prepared vial concentration, amount transferred and verified final total preparation volume.
Check final concentrationPrepared vial + prescribed mg
Find the mL to withdraw
If the vial concentration is already verified and you only need the volume containing a prescribed dose, use mg → mL.
Calculate withdrawal volumeThese tools do not create medicine preparation instructions
Confirm the medicine, diluent, reconstitution volume or final prepared volume, displacement information, compatibility, stability, route, aseptic process, storage, administration instructions, pharmacy guidance and local policy from the current approved source.
Need more than the calculator?
Go further
Understand
Reconstitution & dilution Guides
Understand reconstitution, dilution and final concentration before applying the arithmetic.
OpenLearn
Medication Preparation pathway
Learn reconstitution and dilution as separate preparation stages.
OpenPractise
Preparation maths practice
Practise reconstitution and dilution calculations by skill level.
OpenApply
Medication & IV clinical cases
Apply preparation maths with medication orders and product information in context.
OpenSafety & checking
Keep the preparation stage attached to every number
Reconstitution, withdrawal and final dilution are different stages. Verify which volume and concentration each value belongs to before calculating.
Safety & checking
Keep the preparation stage attached to every number
Reconstitution, withdrawal and final dilution are different stages. Verify which volume and concentration each value belongs to before calculating.
1.Diluent added ≠ final prepared volume
A product can have powder displacement or a specified final volume. Use the verified prepared result rather than assuming final volume equals diluent added.
2.Reconstitution ≠ dilution
Reconstitution creates a prepared solution from a starting form. Dilution lowers the concentration of an existing solution. Some preparations use both stages.
3.V2 means final total volume
In C1V1=C2V2, V2 is the verified final total volume after dilution, not automatically the amount of diluent to add.
4.Correct maths does not validate preparation
Compatibility, stability, diluent choice, aseptic technique, storage, route and administration instructions come from the approved product or pharmacy source.
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Dilution and concentration calculator FAQs
Quick answers for choosing the correct preparation-maths pathway without turning this hub into a second calculator page.
Dilution and concentration calculator FAQs
Quick answers for choosing the correct preparation-maths pathway without turning this hub into a second calculator page.
Which calculator should I use for a C1V1=C2V2 dilution?
Use the Medication Dilution Calculator when the starting concentration, target concentration, and volume relationship are already known and you need to solve one missing C1V1=C2V2 value.
- It can solve for starting volume, final total volume, starting concentration, or target concentration.
- The medicine or solute and concentration basis must match on both sides of the equation.
- Use the product information or approved preparation source to establish what preparation is permitted.
Which calculator should I use to check a final IV bag concentration?
Use the Final IV Bag Concentration Calculator when the vial solution concentration, medicine-solution transfer volume, and final total preparation volume are already verified.
- It checks the amount transferred and final concentration arithmetic.
- It does not choose the diluent, number of vials, transfer volume, bag, compatibility, stability, or administration instructions.
What if I only need to convert a prescribed dose in mg to mL from a vial concentration?
Use the mg-to-mL calculator with the verified concentration shown after reconstitution or on the medicine label.
- That is a dose-to-volume calculation rather than a C1V1=C2V2 dilution calculation.
- The verified concentration must come from the label, monograph, pharmacy source, or other approved preparation information.
Does MedMaths tell me how to reconstitute or prepare a medicine?
No. These tools check arithmetic from values that have already been verified from an approved medicine or pharmacy source.
- MedMaths does not select a diluent, reconstitution volume, compatibility, stability period, container, route, infusion rate, or aseptic process.
- Product information, pharmacy guidance, protocols, the medication order, and local policy control the real preparation.
References
Sources supporting concentration-volume arithmetic and medication-calculation safety boundaries.
References
Sources supporting concentration-volume arithmetic and medication-calculation safety boundaries.
- OpenStax Pharmacology for Nurses: medication dosage-calculation principles.
- RMIT Learning Lab: liquid medication and proportional calculations.
- The Pharmaceutical Journal: dilution maths using concentration-volume relationships.