Serial Dilution Calculator

Figran

Enter your stock, dilution factor and volume to get every transfer.

  • Transfer volumes
  • Tube diagram
  • Free SVG and PNG
Method

Stock

Tube 1

Series

Dilution factor

Volume

Volume means
Tube labels
More
T11.00 µg/mL100 µL left+ 0 diluentT2500 ng/mL100 µL left+ 100 diluent100T3250 ng/mL100 µL left+ 100 diluent100T4125 ng/mL100 µL left+ 100 diluent100T562.5 ng/mL100 µL left+ 100 diluentFrom T4: 100 µLT631.3 ng/mL100 µL left+ 100 diluent100T715.6 ng/mL100 µL left+ 100 diluent100T87.81 ng/mL100 µL left+ 100 diluent100100Transfers in µL

Stock 200 µL · Diluent 700 µL · Discard 100 µL

TubeConcentrationDilutionTransfer in (µL)Diluent (µL)Total (µL)Volume left (µL)
T11.00 µg/mL1:1200 Stock0200100
T2500 ng/mL1:2100 100200100
T3250 ng/mL1:4100 100200100
T4125 ng/mL1:8100 100200100
T562.5 ng/mL1:16100 100200100
T631.3 ng/mL1:32100 100200100
T715.6 ng/mL1:64100 100200100
T87.81 ng/mL1:128100 100200100
Plate count

CFU/mL = 150 ÷ (0.1 mL × 1:1) = 1500 CFU/mL

Serial dilution examples

T11.00 µg/mL100 µL left+ 0 diluentT2500 ng/mL100 µL left+ 100 diluent100T3250 ng/mL100 µL left+ 100 diluent100T4125 ng/mL100 µL left+ 100 diluent100T562.5 ng/mL100 µL left+ 100 diluentFrom T4: 100 µLT631.3 ng/mL100 µL left+ 100 diluent100T715.6 ng/mL100 µL left+ 100 diluent100T87.81 ng/mL100 µL left+ 100 diluent100100Transfers in µL

Two-fold dilution, 8 tubes

Typical values

Stock110⁻¹1:109 mL left+ 9 diluent10⁻²1:1009 mL left+ 9 diluent110⁻³1:10009 mL left+ 9 diluent110⁻⁴1:100009 mL left+ 9 diluent110⁻⁵1:1000009 mL left+ 9 diluentFrom 10⁻⁴: 1 mL10⁻⁶1:100000010 mL left+ 9 diluent1Transfers in mL

Ten-fold bacterial dilution for plate counts

Typical values

S11.00 ng/mL250 µL left+ 0 diluentS2500 pg/mL250 µL left+ 250 diluent250S3250 pg/mL250 µL left+ 250 diluent250S4125 pg/mL250 µL left+ 250 diluent250S562.5 pg/mL250 µL left+ 250 diluentFrom S4: 250 µLS631.3 pg/mL250 µL left+ 250 diluent250S715.6 pg/mL250 µL left+ 250 diluent250250S00 pg/mL250 µL left+ 250 diluentTransfers in µL

ELISA standard curve

Typical values

T11×10⁷ copies/µL45 µL left+ 0 diluentT21×10⁶ copies/µL45 µL left+ 45 diluent5T31×10⁵ copies/µL45 µL left+ 45 diluent5T41×10⁴ copies/µL45 µL left+ 45 diluent5T51×10³ copies/µL45 µL left+ 45 diluentFrom T4: 5 µL5Transfers in µL

qPCR standard curve

Typical values

Stock2T110.0 µM100 µL left+ 198 diluentDiscard 53.853.8T23.16 µM100 µL left+ 100 diluent46.2T31.00 µM100 µL left+ 100 diluent46.2T4316 nM100 µL left+ 100 diluent46.2T5100 nM100 µL left+ 100 diluentFrom T4: 46.2 µLT631.6 nM100 µL left+ 100 diluent46.2T710.0 nM100 µL left+ 100 diluent46.2T83.16 nM100 µL left+ 100 diluent46.246.2Transfers in µL

Half-log dose-response series

Typical values

T164.0 µg/mL100 µL left+ 0 diluentT232.0 µg/mL100 µL left+ 100 diluent100T316.0 µg/mL100 µL left+ 100 diluent100T48.00 µg/mL100 µL left+ 100 diluent100T54.00 µg/mL100 µL left+ 100 diluentFrom T4: 100 µLT62.00 µg/mL100 µL left+ 100 diluent100T71.00 µg/mL100 µL left+ 100 diluent100T8500 ng/mL100 µL left+ 100 diluent100T9250 ng/mL100 µL left+ 100 diluentFrom T8: 100 µLT10125 ng/mL100 µL left+ 100 diluent100100Transfers in µL

MIC two-fold series

Typical values

How to do a serial dilution

  1. Enter your stock

    Enter the concentration and unit.

  2. Choose the factor and tubes

    Set the dilution factor and number of tubes.

  3. T11.00 µg/mL100 µL left+ 0 diluentT2500 ng/mL100 µL left+ 100 diluent100100Transfers in µL

    Follow the transfers

    Add diluent, transfer and mix at each step.

Serial dilution formula

Cn = C0 / Fn−1

Dilution factor

Multiply each step’s factor to find the cumulative dilution. For a volume V left in each tube, transfer T = V / (F − 1).

Worked example

For eight two-fold tubes leaving 100 µL, start with 200 µL stock and add 100 µL diluent to each later tube. Transfer 100 µL at each step and discard 100 µL from the last tube.

Single dilution calculator (C1V1 = C2V2)

V1 = C2V2 / C1. To prepare 10 mL of 100 mM from 1 M stock, mix 1 mL stock with 9 mL diluent.

CFU/mL calculator from plate counts

CFU/mL = colonies / (volume plated in mL × dilution fraction). For 150 colonies from 0.1 mL of a 10⁻⁵ dilution, the stock contains 1.5×10⁸ CFU/mL.

FDA BAM Chapter 3 (January 2026 edition) and ISO use 15–300 colonies per plate; USDA and AOAC use 30–300; APHA uses 25–250. BAM calls results outside its range estimated.

From tubes to a plate

Seven dilutions can fill a column of a 96-well plate with a blank, or eleven can fill a row. 96 Well Plate Template

Serial dilution FAQ

What is a serial dilution?

A serial dilution is a sequence of dilutions; a constant factor produces a geometric decrease in concentration.

How do I calculate the transfer volume?

For volume V left in each tube, T = V/(F − 1). For total volume S, T = S/F. A two-fold series leaving 100 µL transfers 100 µL; a ten-fold series with 10 mL total transfers 1 mL.

What is the dilution factor of the whole series?

Multiply the factors of each step. The Dilution column shows the cumulative dilution relative to stock.

What is the difference between a serial dilution and a single dilution?

A single dilution uses C1V1 = C2V2. A series can help when one direct transfer would be too small.

What should I do if the transfer volume is below 1 µL?

Increase the volume or use an intermediate dilution. The calculator suggests a volume based on your smallest pipette volume.

Should I discard from the last tube?

Discard the final transfer if all tubes must contain the same remaining volume.

How do I calculate CFU/mL?

Divide colonies by plated volume in mL and by the dilution fraction. Check the applicable countable range.

How do I add extra volume for pipetting loss?

Enter Extra volume % under More. Calculations stay in your browser.

FDA BAM Chapter 3 (January 2026 edition); ISO; USDA; AOAC; APHA. Wiegand et al., Nature Protocols, 2008; Bustin et al., Clinical Chemistry, 2009.

Plan your dilution series

Enter your values and download the diagram.