I am using the erase tool to remove the area covered by one feature class (269 sq mi) from another feature class (1617 sq mi). 1617-269 = 1348. However, the result of the erase gives me a feature class that covers 1391 square miles. I expect a little discrepancy, but 43 square miles difference seems like a lot to me. The the only setting for the erase tool is XY tolerance, which I have played with, but it has not helped me. Is there anything that I can do about this?
Can you delete all your duplicate posts. I will move this to managing data where it will get some attention. In the future you can use the 'Share' option to the upper right of your post... it will get shared and not make duplicates.
Make sure that :
The Erase feature is totally within Input feature.
You can use intersect tool for the two feature classes and check geometry area.
Finally calculate the area for Erased feature or intersect feature according to same projection along with input feature and erase feature and data frame.