Is there a way to write a successful circular formula?

I'm trying to write a formula that is circular in nature. From a fundamental standpoint, I can see why it doesn't work however I'm hoping there is another way to approach this.

I'm a police officer working in an investigative unit. My Detective Sergeant would like to track the number of hours spent on each investigation. I would like to create a formula in our spreadsheet that would allow us to add the new numbers and keep a cumulative total. So for instance.

If I want to add 8 hours into cell C5 because I spent 8 hours on that case today. And perhaps in D5 I have the number of hours that I have already worked on this case prior to today, for illustration purposes let's say that number is 37. How do I write the formula so that the 8 hours I worked on the case today gets added to the 37 hours that I have already worked on this case giving me a new total of 45 and then have the ablitily to repalce the number in C5 tomorrow with the hours that I work tomorrow on that case.

If I simply create formula in E5 such as =SUM(C5,D5). Then I get the right answer but then there is no update to the new number if I need to add more hours in tomorrow. D5 will still read 37 instead of the new total that is 45. If I try to do a formula in D5 which is simply =E5, I'm creating a circular formula and even if it worked, since I have a value of 8 in C5 it's going to indefinitely keep adding 8 to the new total that keeps getting updated in D5 but obviously that can't work.

Is there any other way to attack this issue or create this sort of functionality.

You can set up your data similar to the attached.

Hello officer =)

From your set up table, it seems that you can do a pivot table where it'll show you the month and the cases with respect to the hours you've worked.

The only 'downfall' to this is that you have to 'refresh' after new data has been input.

Thanks for the replies, as it turns out I have to head out of the office now to log a few more hours on a new case. I'll have to try these ideas out when I get back.

I'm not overly proficient at excel, so I'm going to be a bit trying to work through these possible solutions. In the meantime just in case it makes it clearer I will give you a rough idea of what I have going on so far.

So each row has the case number, the officer in charge of the case, victim name, suspect name, ages for both, *** for both ,status of the case etc. so ideally I want on the same row as each case to add a few columns so that officers could come in after working on a case, open up the spreadsheet and then just drop how many ours they worked into the appropriate cell and the next cell over would perform the function of adding the number of hours worked today to the existing total number of hours worked on the case so far.

ChemistB, I was able to get this to work. Many thanks to all for your ideas.

Sorry to re-visit this but suppose I want to create another multi-cell script on the same page, is this possible?
For instance the script supplied by ChemistB worked exactly as I wanted it to. I have it set up so that all the numbers that are entered into cells H:3 to H:500 are tallied into cells I:3 to I:500 respectively. So now if I want to do the same thing with cells J:3 to J:500 and have them tally into cells K:3 to K500 respectively, how do I do it? I've tried some different things none of them work.

Of course it does... You always have the answers... Unbelievable!!!
Thanks a million...