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Serial Dilution Calculator

Calculate concentrations at each step of a serial dilution and the transfer volume needed between steps.

Starting/stock concentration (any unit: mg/mL, uM, etc.).
Dilution factor at each step (e.g. 10 for 1:10 dilutions).
Number of dilution steps.
Volume of diluent (e.g. water or buffer) added per step in uL.

Results

Step 1 Concentration100.0,000 (Step 1)
Step 2 Concentration10.0,000 (Step 2)
Step 3 Concentration1.000,000 (Step 3)
Step 4 Concentration0.100,000 (Step 4)
Step 5 Concentration0.01,000,000 (Step 5)
Step 6 Concentration0.00,100,000 (Step 6)
Transfer Volume per Step11.11 uL to transfer each step

📖What is it?

A serial dilution reduces a stock solution concentration by a fixed factor at each step. It is used in microbiology (colony counts), pharmacology (dose-response curves), and immunology (antibody titration). The C1V1 = C2V2 principle governs each step.

🎯How to use

Enter your stock concentration (in any unit -- the output will be in the same unit), dilution factor per step, number of steps, and the volume of diluent to add per step. The transfer volume is how much of the previous step to pipette into the diluent.

💡Example scenario

Starting at 1,000 mg/mL, 1:10 dilutions with 100 uL diluent per step: transfer 11.1 uL into 100 uL. Step 1 = 100, Step 2 = 10, Step 3 = 1, Step 4 = 0.1, Step 5 = 0.01, Step 6 = 0.001 mg/mL. A 10^6-fold range in 6 steps.

🏆Pro tip

Use a fresh pipette tip for every transfer step to prevent carryover contamination. For accurate colony counts in microbiology, plate steps 3-5 (10^-3 to 10^-5 for typical bacterial cultures). Log-scale plotting of concentration vs. response is standard for dose-response analysis (IC50 determination). Parallel dilutions (single-step from stock) are more accurate but use more material.