Westgard QC Online QC Calculator

James O. Westgard and Paul Schilling

This is a training and education tool for quality control in healthcare laboratories. It is designed to help users to calculate basic quality control data, such as mean, standard deviation, cumulative mean, cumulative standard deviation, etc.

In addition to these basic quality control calculations, users may also create control charts with different defined control limits, as well as histograms. Specifically, users will be able to create Levey-Jennings Control Charts that are best suited for healthcare laboratories. These control charts will be "blank" - with control lines drawn but no data plotted.

Note that the graphics generated will "pop up" - you will need to allow pop up windows in your browser.

Please let us know what you think of them.

See QC - The Calculations for an explanation and equations for these calculations.<
See QC Calculator Problem Set if you want to work with some sample data.
NOTE: These Javascript Calculators only work on browsers that support Javascript!

Fill these blanks in if you want to print out a hard copy of your data after you enter it
Control Material  

Monthly Mean, Standard Deviation & CV

Enter up to 40 measurements, then click the buttons to obtain the calculated values for the mean, standard deviation, and CV. Blank entry boxes are not included in the calculations but zeros are.



Cumulative/Lot-to-Date Calculator for
Mean, Standard Deviation, and CV 

To calculate cumulative control limits, enter the previous month's figures for n, sum of x, and sum of x squared, then push the "Total" button. To calculate monthly control limits, just push the "Total" button and only the monthly figures will be used.  

See QC - The Calculations for more information about these calculations 
Previous month's 
(or months') data
This month's data

Sum of x
Sum of x2





Control Chart Plotter

Enter the control mean:   
Enter the control standard deviation:  
Enter up to 3 control limits you wish to evaluate 
(enter the multiplier number only, i.e. 2, 3, 3.5, etc.):
Number of values along the X axis:
The number of data points you wish to plot 
Plot provided data points:   
Create large chart: 
Must be printed landscape
Plot control chart:  

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WesTgard® Quality Corporation, 7614 Gray Fox Trail, Madison WI 53717
Call 608-833-47183 or e-mail us at westgard@westgard.com