How is summation of hatch areas calculated in AutoCad?

Just launch the AREA command and select "Add area", then "Object", and start clicking on the objects. It will list each area as you select it, highlight the selected object so you don't click it twice, and give you the sum at the end.

I am agree with experts...........

Only write "LI" & Select the hatched area & press "Enter" to get all data about it (Primeter,Area, Etc ....)

make the item as one area, and from geometry details find the area

 to create boundaries for each and send "area" command, enter "add", enter "o" for object, and select boundaries

In complicated shaped hatches and large drawings, it is too difficult to creat boundaries by polylines, hench this pratice is not easy way to calculate area.

The easiest way is to upload applications which can be created by user define option in autocad.

By this way, sum of areas of complicated shaped hatches can be easily calculated just by one selection.

an easy way is to create boundaries for each and send "area" command, enter "add", enter "o" for object, and select boundaries (polylines).

I agree with the answers of experts