What is the Serial Dilution Calculator?

Plan serial dilutions with this free serial dilution calculator. Set starting concentration, fold factor per step, and tube volume — get a full dilution table with log₁₀ values, transfer and diluent volumes, and step-by-step lab procedure. Find how many steps reach a target concentration or set up CFU plate-count schemes. Runs instantly in your browser.

How to use the Serial Dilution Calculator

Choose Plan Dilution, Find Steps, or Plate Count mode.
Enter starting concentration, dilution factor per step (e.g., 10×), and volume per tube.
For Find Steps, enter a target concentration to calculate required dilutions.
Review the dilution table: Stock, D1, D2… with concentrations and pipette volumes.
Copy the full table and lab procedure for your notebook.

Common use cases

Preparing standard curves for spectrophotometry or ELISA
Setting up 10-fold serial dilutions for microbiology plate counts
Finding how many steps to dilute a stock to working concentration
Planning transfer volumes for multi-tube dilution series
Teaching serial dilution technique in lab courses

Frequently asked questions

What is a serial dilution?: A serial dilution repeatedly dilutes a solution by the same factor at each step. Four 1:10 steps give a total 10,000× dilution (10⁴). Each step transfers a small aliquot into fresh diluent.
How do you calculate serial dilution steps?: Steps needed = ⌈log(C₀/C_target) / log(factor)⌉. For example, going from 1 M to 0.0001 M with 10× steps requires 4 steps because 10⁴ = 10,000.
How much do I transfer each step?: For a factor-N dilution in total volume V, transfer V/N of the previous tube and add V − V/N diluent. A 1:10 in 1 mL means 100 µL transfer + 900 µL diluent.
How is this used for plate counts?: Serial dilutions of bacterial cultures produce countable colony plates (30–300 colonies). Start from estimated CFU/mL and dilute until a plated aliquot gives a countable range.
What is cumulative dilution factor?: After n steps of factor F, cumulative dilution = Fⁿ. Three 10× steps give 1,000× total dilution; concentration is divided by 1,000 at each cumulative step.

More Scientific Tools

Tube

Concentration

log₁₀

Cumulative

Transfer

Diluent

Stock

1 M

1×

—

0.1 M

-1

10×

100 µL

900 µL

0.01 M

-2

100×

100 µL

900 µL

0.001 M

-3

1000×

100 µL

900 µL

0.0001 M

-4

10000×

100 µL

900 µL

What is the Serial Dilution Calculator?

How to use the Serial Dilution Calculator

Choose Plan Dilution, Find Steps, or Plate Count mode.

Enter starting concentration, dilution factor per step (e.g., 10×), and volume per tube.

For Find Steps, enter a target concentration to calculate required dilutions.

Review the dilution table: Stock, D1, D2… with concentrations and pipette volumes.

Copy the full table and lab procedure for your notebook.

Frequently asked questions

What is a serial dilution?

A serial dilution repeatedly dilutes a solution by the same factor at each step. Four 1:10 steps give a total 10,000× dilution (10⁴). Each step transfers a small aliquot into fresh diluent.

How do you calculate serial dilution steps?

Steps needed = ⌈log(C₀/C_target) / log(factor)⌉. For example, going from 1 M to 0.0001 M with 10× steps requires 4 steps because 10⁴ = 10,000.

How much do I transfer each step?

For a factor-N dilution in total volume V, transfer V/N of the previous tube and add V − V/N diluent. A 1:10 in 1 mL means 100 µL transfer + 900 µL diluent.

How is this used for plate counts?

Serial dilutions of bacterial cultures produce countable colony plates (30–300 colonies). Start from estimated CFU/mL and dilute until a plated aliquot gives a countable range.

What is cumulative dilution factor?

After n steps of factor F, cumulative dilution = Fⁿ. Three 10× steps give 1,000× total dilution; concentration is divided by 1,000 at each cumulative step.