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๐Ÿงช Serial Dilution Calculator

Calculate concentrations across each step of a serial dilution. Ideal for standard curve preparation and microbiological assays.

per step
Step Dilution Concentration Volume to Transfer Diluent to Add
๐Ÿ’ก Tip: For a 1:2 dilution enter factor 2. For 1:10 enter 10. For 2-fold dilution enter 2. "Volume per Tube" is the total final volume in each tube โ€” transfer the listed amount from the previous tube, then top up with diluent to reach that volume.
โš ๏ธ Verify before use: This calculator is a convenience aid. Double-check critical dilutions independently before use in experiments, especially for sensitive reagents or assays.
๐Ÿ“– Example: To prepare a 1:2 serial dilution series from 1 mg/mL stock in 1 mL tubes (transfer 0.5 mL each step): enter Stock = 1 mg/mL, Dilution Factor = 2, Tube Volume = 1 mL, Steps = 5. The table gives you tube-by-tube concentrations and volumes. Use "Copy Table" to paste into Excel or your lab notebook.
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Standard curves

Perfect for preparing 6-point or 8-point calibration curves for HPLC and ELISA.

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Up to 20 steps

Calculate serial dilutions across up to 20 steps in one go.

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Always free

No sign up, no limits. Use as many times as you need.

โœ” Formulas last verified against primary references: March 2025  ยท  Report an error
โš ๏ธ Report an incorrect calculation

Frequently asked questions

What is a dilution factor and how does it compound across steps?

The dilution factor is how many times more concentrated the previous step is compared to the current one (e.g. a factor of 10 means each step is diluted 1:10). Across multiple steps, the total dilution compounds multiplicatively โ€” after n steps at factor DF, the total dilution is DF raised to the power n, which is why serial dilution can reach extremely low concentrations from a manageable series of small, accurate pipetting steps.

Why use serial dilution instead of one large single dilution?

A single very large dilution factor (e.g. 1:1,000,000) would require pipetting an impractically small stock volume, introducing significant pipetting error. Serial dilution breaks this into a chain of smaller, more accurately pipettable steps that multiply together to reach the same overall dilution.

How many dilution steps can this calculator handle?

This calculator supports up to 20 sequential dilution steps, outputting the concentration at each step in a full table โ€” enough for standard curve preparation, serial titers, and most laboratory dilution series.

Accuracy & how this is derived

Derivation: Each step applies the same dilution equation (C1V1=C2V2) sequentially, with the output concentration of one step becoming the input stock concentration for the next, compounding the dilution factor multiplicatively across all steps.

Validated against: Standard serial dilution methodology used throughout microbiology, immunology, and analytical chemistry laboratory practice.

โš ๏ธ For educational and research support only โ€” verify critical results independently before use in regulated, clinical, or publication-bound work.

โœ” Last updated: July 2026  ยท  Report an error

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Serial dilution in quantitative biology and microbiology

Serial dilution is used wherever concentrations must span several orders of magnitude: standard curves for ELISA and HPLC, MIC assays, CFU counting, and receptor binding studies. Each tube is diluted by the same factor, so concentrations follow a geometric series. The transfer volume = tube volume รท dilution factor. Use this calculator to plan your dilution scheme before bench work and to check that your chosen factor gives concentrations in the detection range of your assay.