Cell Dilution Factor Calculator
Diluting a stock to a target concentration is everyday bench work, and the C1V1 equals C2V2 relationship makes it exact: the amount of substance (or number of cells) stays the same, so stock concentration times stock volume equals final concentration times final volume. Enter your stock concentration, the target final concentration, and the final volume you want, and this calculator returns the dilution factor, the volume of stock to take, and the volume of diluent to add. It works equally for molar solutions and cell suspensions.
Dilution formula
C1 * V1 = C2 * V2 (amount conserved)
stock volume V1 = C2 * V2 / C1
dilution factor = C1 / C2 = V2 / V1
diluent to add = V2 - V1
Example: 100 to 10 in 10 mL takes 1 mL stock + 9 mL diluent
Use the same concentration units for C1 and C2 and the same volume units for V1 and V2.
Dilution context
- A dilution factor of 10 (1:10) reduces concentration to one tenth.
- Cell density (cells per mL) follows the same equation as molar concentration.
- Stock volume plus diluent volume equals the final volume.
- The final concentration must be lower than the stock concentration.
- A zero stock concentration returns n/a.
Cell dilution: frequently asked questions
What is a dilution factor?
The dilution factor is the ratio of final volume to the volume of the original (stock) sample. A dilution factor of 10 means one part stock diluted to ten parts total, so the concentration drops to one tenth of the original.
What is the C1V1 = C2V2 equation?
It states that the amount of substance is conserved during dilution: the stock concentration times the stock volume equals the final concentration times the final volume. Rearranging lets you solve for any one unknown when the other three are known.
How much diluent do I add?
Diluent volume is the final volume minus the stock volume used. For a 1 in 10 dilution to 1 mL, you take 0.1 mL of stock and add 0.9 mL of diluent. The calculator reports both the stock volume needed and the diluent to add.
Does this work for cell suspensions?
Yes. Cell density behaves like concentration in the dilution equation, so C1V1 = C2V2 applies to cells per mL just as it does to molar concentrations. Use the same density units for stock and final.
What if I want the final concentration instead?
Enter the stock concentration, the stock volume, and the final volume, and the calculator gives the resulting final concentration along with the dilution factor. Leave the field you want solved as the output.
Official sources
- NCBI Bookshelf: National Center for Biotechnology Information.
- NIST: National Institute of Standards and Technology.
Reviewed by the CalculatorHub team, edited by James Graham, 17 June 2026. See our methodology.