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Calcimator

Viral Titer Calculator

Calculate viral titer (PFU/mL) from plaque assay data and determine volume needed for target MOI.

Inputs

Results

Titer (PFU/mL)

175,000,000

Titer (log10 PFU/mL)8.24
Average plaques/plate17.5
Volume for MOI (µL)5.71
Volume for MOI (mL)0.01
MOI per 1 µL stock0.18
Total Pfu175,000,000
How to Use This Calculator
  1. Enter the total plaque count and number of replicate plates counted.
  2. Set the dilution exponent (10^-n), volume plated per well (mL).
  3. Enter target MOI and cell count for your infection experiment.
  4. Review Titer (PFU/mL), Volume for MOI (µL), and MOI per 1 µL Stock.
  5. Use Volume for MOI to pipette the correct amount of virus stock for your infection.

How the result changes with Dilution (10^-n)

Dilution (10^-n)Titer (PFU/mL)
2.117,500
4.8517,500,000
8.1517,500,000,000
1117,500,000,000,000

What each input means

Total plaque count
Total plaques counted across all replicate plates at the chosen dilution.
Number of replicates
Number of replicate plates counted (plaque count will be averaged).
Dilution (10^-n)
Negative exponent of dilution. Enter 6 for 10^-6 (1:1,000,000) dilution.
Volume plated (mL)
Volume of diluted virus plated per well/plate in mL.
Target MOI
Desired multiplicity of infection (virus particles per cell).
Target cell count
Number of cells to infect for MOI volume calculation.

What each result means

Titer (PFU/mL)
Calculated viral titer in plaque-forming units per milliliter.
Titer (log10 PFU/mL)
Log10 of viral titer for easy comparison.
Average plaques/plate
Average number of plaques per replicate plate.
Volume for MOI (µL)
Volume of virus stock needed to achieve target MOI.
Volume for MOI (mL)
Volume of virus stock needed to achieve target MOI in mL.
MOI per 1 µL stock
MOI achieved by adding 1 µL of undiluted stock to your cells.

How this is calculated

Worked example, using the default values

  1. Identify Input Parameters
    4 parameters
    Total plaque count = 35, Number of replicates = 2, Dilution (10^-n) = 6, Volume plated (mL) = 0.1 = 6 input(s) provided
  2. Calculate Titer
    Titer = Number(titerPfuPerMl.toExponential(2))
    175000000 = 175000000
  3. Calculate Titer
    Titer = log10(max(1, titerPfuPerMl))
    8.24 = 8.24
  4. Calculate Average plaques/plate
    Average plaques/plate = plaqueCount / numberOfReplicates
    17.5 = 17.5

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