Question: I am working from home this weekend. I am a developer and I have created a program that purges records at the click of a button. The entire process take after clicking about 12 hours to complete. I need to check in on the progress from time to time just in case there are any unexpected errors thrown. So in the beginning stages of the program there were several starts and stops fix something start over again. 

But, now I don't think there will be anymore errors and this weekend I expect the program to run without issue from end to end. I am still monitoring the program and have kept it on a second monitor running for 6+ hours. 

How would I bill for this time although I am not physically writing code I am technically working ?

I would feel guilty to bill for the entire 12 hours while I watch a movie on one screen and monitoring the program in the other.

Also, note that I will need to run this program 7 more times which would be a total 96 approx hours.

Answer: 
Test actions in developments states is also a developer job in order to release or apply for approval, I wouldn't feel guilty at all, you did the code before (I suppose) and now you're at test phase. If you still think it doesn't worth huge bill then just do some simple math: 

bill = (hours\_of\_work \* min\_payrate\_you\_willing\_to\_acept) + taxes\_if\_any;

Hope it was helpful.
Got cable? A phone (without a "minute" plan). You pay for *availability*. The phone company and cable company really don't care if you use the service or not, and they're not charging a fraction of the monthly fee if you don't utilize the service.

Likewise: if you have to be **available** for the process to run from start to finish, charge for the entire time span. That's business.