MPN Calculator
Updated 29-April-2004


Requires Windows 95/98/NT/XP
and Visual Basic 6 run time library

MPN Calculator (VB6 version)

Revision: Build 24, Preinstallation of VBRun60sp6.exe is required. See below for download).

Build 24 correct minimize error
Build 23 correct LL/UL display.
Build 22 adds a user modifiable list of MPN types.
Build 21
has an improved main form. Increased the number of dilutions from 6 to 7.
Build 19 adds copy and paste functions.
Build 18 adds mouse enabled data input and improved data range before an overflow error is encountered.
Build 17 adds the auto calculate mode.


Microsoft Runtime library required by all VB6 programs. If you are already running VB6 programs you do not need this download. If you are unsure, try running MPN Calculator (VB6) first. If it tells you that you need the runtime library come back, download and run VBRUN60sp6.exe to install it. About 1031 kb

Go here to obtain a copy of the Unzip program.

MPN Calculator (VB3 version)

Build 9, 15-Feb-2000
zip file, about 340 kb
(Visual Basic 3 version) (Excel version)

MS Excel version of calculator
about 79 kb

Standard MPN tables are frequently limited to 3 or 4 defined dilutions and 3, 5, or 10 replicate samples per dilution. The MPN Calculator estimates MPN values for up to 6 different dilutions, dilutions can be none standard amounts, the replicates per dilution can vary.. In addition, the 3-tube 3-decimal dilution series frequently used in food microbiology and standard water microbiology dilutions are offered as preprogrammed selections.

Why use an MPN calculator?

I lost my MPN table.
This program replaces paper tables. Tables are used because MPN values are extremely difficult to compute with a standard calculator. A programmed calculator or computer works much better.

I have 4 dilutions and my MPN table is for 3 dilutions, what do I do?.
This program takes input for any number of dilutions (up to 6). So you don't have to guess or throw out data.

The MPN pattern I have (e.g 1-0-3) doesn't appear in my paper table.
This program can compute MPN values for any combination or results, whether the results are probable or not. Note however that combinations which are absent from tables are considered rare and therefore improbable.

Missing a tube or a result?
No problem, enter known information and obtain a valid result.

I analyzed, different quantities than specified in the MPN table. What correction factor should I use?
With the MPN Calculator, enter the data, the calculator does the rest.

The interface and error trapping are almost complete. If you find it useful and provide feedback, I will provide updates.

MPN Dilution Basics by John Lindquist

FDA BAM MPN from Serial Dilutions by Wallace E. Garthwright


Please report bugs or problems with these calculators to me at mcuriale at gmail dot com .
Thank you.