Serial Dilution Calculator

Serial dilution is a lab technique where a solution is repeatedly diluted by a fixed factor to produce a range of progressively lower concentrations. Enter your initial concentration, dilution factor, number of dilution steps, and total volume per step into the Serial Dilution Calculator to get the final concentration, total dilution factor, and the exact stock volume and diluent volume needed at each step. Also try the calculate Cell Concentration, Cells per Liter & Cells per Microliter — OD600 to Cell Number.

Results

Final Concentration

Total Dilution Factor

Stock Volume per Step

Diluent Volume per Step

Results Table

What is a serial dilution?

A serial dilution is a stepwise dilution of a solution that is repeated a certain number of times using the same dilution factor. It's commonly used to create a series of standards with logarithmically decreasing concentrations for calibration curves. See also our Osmolarity Calculator.

How do I choose the right dilution factor?

The dilution factor depends on your concentration range needs. Common factors are 2-fold, 5-fold, or 10-fold. A 10-fold dilution factor creates a wide range quickly, while 2-fold provides more data points in a narrower range.

What is the C1V1 = C2V2 equation?

This is the fundamental dilution equation where C1 is initial concentration, V1 is stock volume, C2 is final concentration, and V2 is final volume. It ensures the amount of solute remains constant during dilution.

How much stock solution do I need for each dilution step?

For each step, you need Total Volume ÷ Dilution Factor of stock solution. For example, with 1000 μL total volume and 10× dilution, you need 100 μL stock + 900 μL diluent. You might also find our use the Cell Dilution Calculator (C1V1=C2V2) useful.

What are common mistakes in serial dilutions?

Common mistakes include using the wrong pipette tips, inadequate mixing between steps, cross-contamination, and calculation errors. Always use fresh tips, mix thoroughly, and double-check calculations.

Why are serial dilutions logarithmic?

Serial dilutions create logarithmic concentration series because each step multiplies the previous concentration by the same factor. This is ideal for assays with logarithmic dose-response relationships.

How do I prepare the first dilution?

For the first dilution, take your calculated stock volume from the original solution and add diluent to reach the total volume. Mix thoroughly before proceeding to the next step.

What diluent should I use?

The diluent should be compatible with your analyte and assay conditions. Common diluents include buffer solutions, culture media, distilled water, or PBS, depending on your specific application.