Cell dilution calculator.
Work out a dilution with C1V1 = C2V2. Enter your stock concentration, the concentration you want and the final volume, and get how much stock and diluent to mix.
Dilution
LiveUses C1V1 = C2V2. Concentrations can be any matching units (such as cells/mL); the volume of stock comes out in the same units as the final volume.
Stock to use (V1)
2 mL
of stock, topped up to 10
Assumes simple mixing with C1V1 = C2V2. Calculations run in your browser; nothing you enter is stored.
How it works
The dilution equation
Diluting a stock follows one rule: C1 times V1 equals C2 times V2. The amount of the original you keep, times its concentration, equals the amount you end up with, times the lower concentration. Rearranged, the stock volume V1 is C2 times V2, divided by C1.
To dilute a 1,000,000 cells/mL stock to 200,000 in a final 10 mL, you need 2 mL of stock and 8 mL of diluent, a 5-fold dilution.
Reference
Dilution factors.
How a dilution factor maps to the ratio of stock to diluent.
| Dilution factor | Stock : diluent |
|---|---|
| 2x | 1 : 1 |
| 5x | 1 : 4 |
| 10x | 1 : 9 |
| 20x | 1 : 19 |
| 100x | 1 : 99 |
The full guide
The complete guide to dilutions.
What C1V1 = C2V2 means, how to use it, and how dilution factors and series work.
The C1V1 = C2V2 rule
The dilution equation says the amount of solute stays the same before and after you dilute: concentration one times volume one equals concentration two times volume two. You usually know three of the four values and solve for the missing one.
To prepare a target concentration in a set final volume, rearrange to V1 = C2 times V2 over C1, which is the stock you need, then top up with diluent to the final volume.
Working out the volumes
First find V1, the stock volume, from C2 times V2 divided by C1. Then the diluent is simply the final volume minus V1. Always add the stock to the diluent and mix, rather than the other way round, for an even result.
Keep the concentration units consistent on both sides; only the ratio matters, so cells/mL, molar or any unit works as long as C1 and C2 match.
Dilution factor
The dilution factor is how many times more dilute the final solution is, equal to C1 divided by C2, or V2 divided by V1. A 5-fold dilution means one part stock to four parts diluent, written 1 to 4.
Knowing the factor is a quick way to plan a dilution without recomputing volumes each time.
Serial dilutions
For very large dilutions, do several smaller steps in series rather than one extreme step, which is more accurate. Three 10-fold dilutions in a row give a 1,000-fold dilution overall, with easy-to-pipette volumes at each stage.
This calculator handles each single step; chain it for a series.
The formula
Same solute,
more volume.
C1V1 = C2V2. Solve V1 = C2V2 / C1 for the stock, then top up with diluent to the final volume.
DNA concentration ›# Dilution equation
C1 × V1 = C2 × V2
V1 = C2 × V2 / C1
diluent = V2 − V1
# worked example
200000 × 10 / 1000000 = 2Questions
Dilution questions.
How do I calculate a dilution?
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Use C1V1 = C2V2. To hit a target concentration in a final volume, the stock you need is V1 = C2 times V2 divided by C1, and the diluent is the final volume minus V1.
How much stock and diluent do I need?
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For a 1,000,000 to 200,000 dilution in 10 mL, you need 2 mL of stock and 8 mL of diluent. Enter your own numbers above for the volumes.
What is the dilution factor?
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It is how many times more dilute the result is: C1 divided by C2, or V2 divided by V1. A 5-fold dilution is one part stock to four parts diluent.
What units should I use?
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Any, as long as C1 and C2 share the same concentration unit. The stock volume comes out in the same unit as the final volume you enter.
Is this cell dilution calculator free?
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Yes. It is completely free with no sign-up, and every calculation runs locally in your browser, so nothing you enter is stored or sent anywhere.
About the developer
Jean Borg
Jean builds and maintains every calculator on freecalculators.pro from Malta, with a focus on tools that are fast, free and show their working. The cell dilution calculator uses the C1V1 = C2V2 rule and is for lab planning and education.