Cell Dilution Calculator

Cell Dilution Calculator

This calculator helps you prepare a final cell suspension at a target concentration by mixing a measured volume of your stock (starting) cell suspension with diluent to reach a requested final volume.

Core dilution formula

Cell dilution is commonly calculated using:

\[ C_1 \cdot V_1 = C_2 \cdot V_2 \]

Where:

• \(C_1\) - starting concentration
• \(C_2\) - target concentration
• \(V_2\) - final total volume you want to prepare
• \(V_1\) - stock volume to transfer

Solving for the stock volume:

\[ V_1 = \frac{C_2 \cdot V_2}{C_1} \]

The diluent volume is:

\[ V_{\text{diluent}} = V_2 - V_1 \]

When serial dilution is needed

If the required stock transfer volume \(V_1\) is too small to pipette accurately, a serial dilution can improve practicality. The idea is to dilute in multiple steps so that every transfer volume stays above a minimum pipettable volume.

The overall dilution factor is:

\[ DF = \frac{C_1}{C_2} \]

If you split the overall factor into step factors \(f_1, f_2, \ldots, f_n\), then:

\[ DF = \prod_{i=1}^{n} f_i \]

Each step reduces concentration by dividing by its step factor:

\[ C_{i} = \frac{C_{i-1}}{f_i} \]

How to use the calculator

1. Enter your starting concentration and units.
2. Enter the target concentration and units.
3. Enter the final volume you want to prepare.
4. Set a minimum pipettable transfer (for example, 2 µL).
5. If a serial dilution is required, set the intermediate step total volume used to build intermediate stocks.
6. Click Calculate to generate the mixing volumes and the step-by-step table.

Interpretation tips

• If starting concentration is lower than target, dilution cannot help. You would need a concentration method rather than adding diluent.
• If the plan shows a warning or critical note, adjust either the final volume, intermediate volume, or the minimum transfer threshold to make the workflow more practical.
• Use consistent lab technique: proper mixing at each step reduces error accumulation in serial dilution.

Example

Suppose \(C_1 = 500{,}000\) cells/mL and you want \(C_2 = 100{,}000\) cells/mL at \(V_2 = 10\) mL:

\[ V_1 = \frac{100{,}000 \cdot 10}{500{,}000} = 2 \text{ mL} \]

\[ V_{\text{diluent}} = 10 - 2 = 8 \text{ mL} \]

So you would transfer 2 mL of stock and add 8 mL of diluent to reach the target.

Limitations

• This calculator addresses concentration and volume math. It does not model viability changes, clumping, or counting uncertainty.
• Serial dilution improves pipetting feasibility but can amplify measurement error across steps.