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Serial Dilution Calculator

Plan a serial dilution: concentration at each tube plus the transfer and diluent volumes for any fold and step count.

Enter the stock concentration, dilution factor, steps and volume per tube.

About this tool

Plan a serial dilution and get the concentration of every tube plus the exact transfer and diluent volumes needed. Enter the stock concentration, the dilution factor, how many steps and the total volume per tube. All calculations run in your browser.

Each step divides the concentration by the dilution factor, so the concentration at tube n is Cn = C0 / DF^n. For a fixed total volume per tube, the transfer volume is total volume / DF and the diluent volume is total volume − transfer volume. For example a 10-fold dilution into 1 mL tubes means moving 0.1 mL and adding 0.9 mL of diluent at each step.

The results table lists every tube from the undiluted stock (tube 0) through the final dilution, showing the dilution ratio (1:DF^n), the concentration and the per-tube transfer and diluent volumes. It is ideal for preparing standard curves, plating assays and titre determinations.

Frequently asked questions

How is the concentration at each tube found?
Every step divides by the dilution factor, so tube n has concentration Cn = C0 / DF^n, where C0 is the stock. A 2-fold series halves the concentration each time; a 10-fold series divides by ten.
How much do I transfer and dilute at each step?
For a constant total volume V per tube, transfer V / DF from the previous tube and add V − V/DF of diluent. With 1 mL tubes and a 10-fold factor that is 0.1 mL transferred and 0.9 mL diluent.
What does 1:DF^n mean?
It is the total dilution of that tube relative to the stock. Tube 1 is 1:DF, tube 2 is 1:DF², and so on, so the final tube is diluted by DF raised to the number of steps.
Is anything sent to a server?
No. The whole dilution plan is generated in your browser from the values you enter, so nothing is uploaded.

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