Serial Dilution Calculator

It is a chain of dilutions where each tube is diluted from the one before it by the same factor. Repeating a modest step, such as 1:10, many times reaches concentrations far lower than a single dilution could accurately mix, which is why it is standard for standard curves, plate counts and titrations.

It divides the total volume after mixing by the volume carried over: (transfer + diluent) / transfer. Moving 1 mL of solution into 9 mL of diluent gives 10 mL total over 1 mL carried, a factor of 10 per step. The diluent may be zero, but the resulting factor must exceed 1.

It is the per-step factor raised to the number of steps. Five tenfold steps give 10 to the fifth power, which is 100000. The final concentration is the starting concentration divided by that total, so a stock of 1 ends at 0.00001.

No. Every step is a pure ratio, so the answer keeps whatever unit you started with, whether molar, mg/mL, CFU/mL, ppm or an OD reading. The tool never assumes a unit, so make sure the stock value you enter is already in the unit you want for the results.

The display switches to scientific notation once a value drops below 0.0001 or climbs to 10 million or more, to keep long strings of zeros readable. The underlying number is exact; only its formatting changes, and the copied text uses the same form.

No. The factor must be greater than 1, so each step always reduces the concentration. Concentrating a solution is a different operation, so if you enter a factor of 1 or less, or volumes that would not dilute, the tool asks you to correct the value.

The step count must be a whole number of at least 1, and there is no hard upper cap. Very deep series push the final concentration toward the limits of floating point, so extreme dilutions may round to zero, which mirrors what happens at the bench when a target falls below detection.

No. The math assumes perfect transfers and complete mixing. Real serial dilutions accumulate error at every step, so long series drift from the ideal values. Treat the output as the target and validate low tubes against a standard when accuracy matters.

No. The whole calculation runs in your browser, so the concentrations and volumes you type never leave your device and nothing is uploaded or stored.