Cell Dilution Calculator
Enter your stock concentration, target concentration, and desired final volume to calculate how much stock solution and diluent you need.
Last updated: September 25, 2026
Frequently asked questions
What do C1, V1, C2, and V2 mean?
C1 is the concentration of your stock (starting) solution, V1 is the volume of stock solution you need to use, C2 is the target (final) concentration you want, and V2 is the total final volume after dilution. The relationship C1 × V1 = C2 × V2 holds because the total amount of substance stays the same - only the concentration changes as you add diluent.
How do I calculate diluent volume instead of stock volume?
Diluent volume is simply the final volume minus the stock volume: diluent = V2 - V1. This calculator shows both automatically once it solves for V1, so you know exactly how much stock solution and how much diluent (buffer, media, or solvent) to combine.
What if I need to solve for a different variable, like final volume instead of stock volume?
The same equation rearranges for any of the four variables: V1 = C2V2/C1, V2 = C1V1/C2, C1 = C2V2/V1, or C2 = C1V1/V2. This calculator is set up for the most common lab scenario (starting from a known stock and target, solving for how much stock to use) - for other combinations, rearrange the equation with your known values.
Can this be used for serial dilutions?
This calculator handles a single dilution step. For a serial dilution (a series of sequential dilutions, each using the previous step's result as the new stock), run this calculation once per step, using each step's target concentration as the next step's stock concentration (C1).
Why did I get an error saying the target exceeds the stock concentration?
A simple dilution with diluent can only decrease concentration, never increase it - if your target concentration (C2) is higher than your stock concentration (C1), you'd need a more concentrated stock, or you'd need to concentrate your existing sample through a method like centrifugation or evaporation rather than diluting it.
Do the concentration units matter for this calculation?
The math itself is unit-agnostic as long as C1 and C2 use the same unit (both in cells/mL, both in molarity, both in mg/mL, etc.) - the equation cancels the units out. Just make sure you're consistent, since mixing units (like entering C1 in cells/mL and C2 in cells/L) will give an incorrect result.