Multi-step Serial Dilution Calculator
Calculate final concentration after N repeated serial dilutions using a constant factor.
Any units (e.g., mg/mL, ng/mL, CFU/mL) — just stay consistent.
Factor 10 = 1:10 each step. Factor 2 = 1:2 each step.
Whole number only.
Educational use only. Always verify against lab SOPs/local policy.
How multi-step serial dilution works
In a serial dilution, you apply the same dilution factor repeatedly (for example, 1:10 each step). Each step divides the concentration by the factor. After multiple steps, the overall reduction is the factor raised to the power of the number of steps.
Formula
Worked examples
Example 1: 1:10 repeated for 3 steps
Cstart = 1000 mg/mL, factor = 10, steps = 3
Example 2: 1:2 repeated for 4 steps
Cstart = 80 CFU/mL, factor = 2, steps = 4
Example 3: 1:5 repeated for 5 steps
Cstart = 500 ng/mL, factor = 5, steps = 5
When this calculator is used
- •Creating dilution series for standard curves
- •Microbiology plating and CFU workflows
- •Antibody/antigen titration in immunoassays
- •Analytical chemistry method development
- •QC / validation dilution series checks
Reminder: serial dilution errors can compound across steps. Use calibrated equipment, mix properly, and verify critical points where required.
Related calculators
Frequently asked questions
Clinical reminder: Always follow local protocols and consult medication information sheets. These examples are for calculation practice only.
References & sources
These are credible sources for dilution concepts, laboratory practice, and unit standards.