When to use this calculator
Concentration averages must be weighted by volume when the amounts of the two solutions differ.
Explore the concentration & mixtures calculators for other questions in this topic. For a related calculation, use the Solvent Addition for Dilution Calculator: Estimate solvent addition needed to dilute a fixed stock-solution volume.
PUTTING IT INTO PRACTICE
Solution Mixing: a worked example
The values below are an illustrative example, not a recommendation. Replace them with measurements or assumptions that match your question.
| Input | Example value |
|---|---|
| First concentration | 1 |
| First volume (L) | 2 |
| Second concentration | 3 |
| Second volume (L) | 2 |
| Result | 2 input concentration units |
- Check the input labels and enter the example values above.
- Apply the relationship: Final concentration = (C₁V₁ + C₂V₂)/(V₁+V₂).
- The result is 2 input concentration units, rounded for display.
How to interpret your result
Concentrations must use the same units; assumes additive volumes, the same solute and no reaction.
Keep mass, amount and volume definitions separate. Molarity uses final solution volume; molality uses solvent mass. A dilution cannot increase concentration without some process beyond adding solvent.
Frequently asked questions
Are molarity and molality interchangeable?
No. Molarity is amount per solution volume, while molality is amount per solvent mass.
When is the solution mixing calculator useful?
Concentration averages must be weighted by volume when the amounts of the two solutions differ.
How do I use the solution mixing calculator?
Enter first concentration, first volume (l), second concentration, second volume (l). The result updates automatically. Use the units shown beside each input; the example values illustrate the method.
Which formula does this calculator use?
Final concentration = (C₁V₁ + C₂V₂)/(V₁+V₂).
What should I check before using the result?
Concentrations must use the same units; assumes additive volumes, the same solute and no reaction.
How are results rounded?
Scalar numbers display up to six decimal places, with scientific notation for very large or small values. Text, fraction, date and schedule outputs use the format described on the tool. Intermediate calculations use JavaScript floating-point arithmetic. Keep sensible precision for your measurements.
Further reading
For background on this topic, see OpenStax: molarity and dilution ↗. This is a topic reference, not an external review or endorsement of this tool.
Calculators Map editorial process · Updated · Methods and limitations