These lens calculators are for macro machine vision lenses, used to image small objects.
These calculators have already applied the pixel size and resolution of the CABR219 Basler Ace U acA640-300gc camera with ON Semi Python 300 sensor having 4.80 x 4.80 micron pixels and 640 x 480 resolution.
Note you may specify an area-of-interest smaller than the camera's full resolution.
All dimensional values are in millimeters.
First enter your application parameters in Calculator #1. This will help you determine the ideal lens magnification.
You're not likely to find a lens having the exact magnification suggested by Calculator #1.
Typically, you'll want to select the first available lens having a lower magnification.
This will result in a slightly larger field of view.
You can use Calculator #2 to determine the field of view provided by a lens having a particular magnification.
Calculators assume field of view width is in direction of the camera sensor's width.
If your field of view's height is greater than it's width, consider rotating the camera 90 degress.
If the calculator is suggesting a lens having a magnification less than .33, then you probably don't need a macro lens.
Try an entocentric lens instead.
There are many other factors to consider beyond lens magnification. We'd be glad to help you select a lens appropriate for your project.