Hi,

I am trying to display the time spent logged in to Sheet1 using a login script
The login time is entered into cell (A1) and the logout time entered into cell (B1)
Using =NOW() copied from another cell.

the time is then calculated in cell (C1) however I would like to keep an ongoing record of the time logged in, so each time the user logs in the time is added to the previous time instead of overwriting it. I have tried the following with no luck, as a circular reference error occurs 

=C1=C1+B1-A1
is there a VBA code for this?

thanks for any help on this

Regards

Steven