Serial Dilution Calculator
Calculate the diluent volume and tk target concentrations across each step of a logarithmic or linear serial dilution.
Dilution Configuration
Define your starting concentration and dilution parameters.
Diluent Volume per Tube
* Put this volume of diluent in each subsequent tube.
Tip Change Hygiene
Always change pipette tips between dilution tubes to prevent carryover contamination.
Step-by-Step Dilution Scheme
| Tube Number | Volume of Diluent | Volume to Transfer | Final Concentration |
|---|
Common Serial Dilution Ratios & Laboratory Standards Reference
| Dilution Factor & Ratio | Example Setup (Transfer + Diluent) | Concentration per Step | Primary Assay Application |
|---|---|---|---|
| 10-fold (1 : 10) | 100 μL + 900 μL diluent | 10⁻¹, 10⁻², 10⁻³, 10⁻⁴... | Bacterial CFU counts, qPCR standard curves |
| 2-fold (1 : 2) | 500 μL + 500 μL diluent | 1/2, 1/4, 1/8, 1/16, 1/32... | MIC antimicrobial susceptibility testing, antibody titers |
| 5-fold (1 : 5) | 200 μL + 800 μL diluent | 20%, 4%, 0.8%, 0.16%... | Protein standard curves (BCA / Bradford assays) |
Calculation Methodology & Equations
Diluent Volume Equation
Calculates diluent required per tube to maintain a constant step-wise dilution factor.
Concentration Step Function
Determines concentration $C_n$ at step $n$ relative to initial stock concentration $C_0$.
Frequently Asked Questions
What is a 10-fold serial dilution? ▼
A 10-fold (1:10) serial dilution reduces the concentration of solute or microbes by a factor of 10 at each step (e.g. 100%, 10%, 1%, 0.1%, 0.01%).
How do you calculate diluent volume per step? ▼
Diluent Volume = Aliquot Transfer Volume × (Dilution Factor - 1). For a 1:10 dilution with 100 μL transfer volume, diluent volume = 100 μL × (10 - 1) = 900 μL.
What applications require serial dilutions? ▼
Serial dilutions are used in microbiology (CFU plate counts), immunology (ELISA standard curves), pharmacology (dose-response curves), and molecular biology (qPCR standard curves).
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