Serial Dilution Calculator
Enter the starting concentration, the fold dilution per step and how many steps you run. The calculator returns the total dilution factor and the concentration at every tube.
How to calculate a serial dilution
- Enter the starting (stock) concentration.
- Set the dilution factor per step, or enter the transfer and diluent volumes to derive it.
- Enter the number of steps and read the concentration after each tube.
Examples
Tenfold series
1 M stock, 10x factor, 5 steps
Total factor 100000, final 1e-5 M
Factor from volumes
1 mL transfer + 9 mL diluent
Dilution factor = 10 per step
Frequently asked questions
What is a serial dilution?
A serial dilution is a stepwise dilution where each tube dilutes the previous one by the same factor. It spans a wide concentration range using small, repeated steps.
How is the dilution factor calculated from volumes?
Divide the total volume after mixing by the volume carried over. Transferring 1 mL into 9 mL of diluent gives 10 mL over 1 mL, a factor of 10 per step.
What is the total dilution factor?
It is the per-step factor raised to the number of steps. Five tenfold steps give 10 to the 5th power, a total dilution of 100000 from the original stock.
How do I find the final concentration?
Divide the starting concentration by the total dilution factor. A 1 M stock diluted 100000-fold ends at 0.00001 M, or 1 times 10 to the minus 5.
Does the unit matter?
No. The calculation is a ratio, so the result keeps whatever concentration unit you start with, whether molar, mg per mL, CFU per mL or any other.
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