Need a formula for a Marketing equipment log

[crystl416]

I am trying to create an equipment log in excel that will automatically
update what equipment is in stock based on an entry log worksheet in the same
file.
Currently I have a list of items and next to each item is a cell that holds
a formula for calculating any check outs of equipment that are entered on the
entry log.
I do not want to have another page for returns, but instead to only have to
enter the date that the item has been returned on the same row as the
original check out.
I want this to then it turn, return the checked out item to the running
stock total.

Any ideas on how to do this? I was trying something with an array formula
involving INDEX and SMALL, but I just wasn't getting the final result.

 

[Sean Timmons]

So, do you have something like this:

=counta(A2:A1000)-counta(B2:B1000) to count the number of items that are in
stock and subtract those that are checked out?

If so, you can merely add +counta(C2:C1000) to the end....