When to use this calculator
Find stock volume required for a target diluted concentration. Both concentrations must use the same units; dilution cannot increase concentration.
Explore the concentration & mixtures calculators for other questions in this topic. For a related calculation, use the Dilution Factor Calculator: Express a concentration reduction as a dilution multiple.
PUTTING IT INTO PRACTICE
Dilution: 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 |
|---|---|
| Stock concentration | 1 |
| Target concentration | 0.1 |
| Final volume (mL) | 250 |
| Result | 25 mL |
- Check the input labels and enter the example values above.
- Apply the relationship: Stock volume = target concentration × final volume ÷ stock concentration.
- The result is 25 mL, rounded for display.
How to interpret your result
Both concentrations must use the same units; dilution cannot increase concentration.
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.
How do I use the dilution calculator?
Enter stock concentration, target concentration, final volume (ml). The result updates automatically. Use the units shown beside each input; the example values illustrate the method.
Which formula does this calculator use?
Stock volume = target concentration × final volume ÷ stock concentration.
What should I check before using the result?
Both concentrations must use the same units; dilution cannot increase concentration.
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