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MOI Calculator

Work out the volume of virus to add to your cells for the multiplicity of infection you want. Use it when transducing cells with lentivirus or AAV, or infecting with any titered virus or phage.

Enter your cell numbers, the multiplicity of infection you want and your virus titer. We'll tell you how much virus stock to add to each well, and what share of cells to expect infected.

How many cells there are when you infect, e.g. 100000 or 1e5.

cells

How many you are infecting.

Infectious particles per cell, e.g. 0.3 or 5.

From your titration or the datasheet, e.g. 1e8.

Rounded up to whole wells.

%
Enter your values and press Calculate to see how much virus to add.

How it's calculated

Virus needed per well = cells per well × MOI

Volume per well = virus needed ÷ titer (TU/mL, PFU/mL…)

Infected cells = 1 − e^−MOI

The infected fraction follows the Poisson distribution: at MOI 1 about 63% of cells receive at least one particle. When the volume per well is too small to pipette, the calculator suggests a 10-fold dilution of the stock.