This post builds on earlier discussion, How many hours did Johnny work? I recommend you to read that post too.
Lets say you have 2 dates (with time) in cells A1 and A2 indicating starting and ending timestamps of an activity. And you want to calculate how many workings hours the task took. Further, lets assume,
- Start date is in A1 and End date is in A2
- Work day starts at 9 AM and ends at 6PM
- and weekends are holidays
Now, if you were to calculate total number of working hours between 2 given dates, the first step would be to understand the problem thru, lets say a diagram like this:

We would write a formula like this:
=(18/24-MOD(A1,1)+MOD(A2,1)-9/24)*24 + (NETWORKDAYS(A1,A2)-2)*9
See the above illustration to understand this formula.
Now, while this formula is not terribly long or ineffective, it does feel complicated.
May be we can solve the problem in a different way?!?
Michael left an interesting answer to my initial question, how many hours did Johnny work?
Pedro took the formula further with his comment.
The approach behind their formulas is simple and truly out of box.
Instead of calculating how many hours are worked, we try to calculate how many hours are not worked and then subtract this from the total working hours. Simple!
See this illustration:

So the formula becomes:
Total working hours between 2 dates – (hours not worked on starting day + hours not worked on ending day)
=NETWORKDAYS(A1,A2)*9 - (MOD(A1,1)-9/24 + 18/24 -MOD(A2,1))*24
After simplification, the formula becomes,
=NETWORKDAYS(A1,A2)*9 - (MOD(A1,1) -MOD(A2,1))*24 -9
=(NETWORKDAYS(A1,A2)-1)*9 +(MOD(A2,1)-MOD(A1,1))*24
Sixseven also posted an equally elegant formula that uses TIME function instead of MOD()
=(NETWORKDAYS(B3,C3)*9) - ((TIME(HOUR(B3),MINUTE(B3),SECOND(B3))-TIME(9,0,0))*24) - ((TIME(18,0,0)-TIME(HOUR(C3),MINUTE(C3),SECOND(C3)))*24)
Download the solution Workbook and play with it
Click here to download the solution workbook and use it to understand the formulas better.
Thanks to Pedro & Michael & Sixseven & All of you
If someone asks me what is the most valuable part of this site, I would proudly say, “the comments”. Every day, we get tens of insightful comments from around the world teaching us various important techniques, tricks and ideas.
Case in point: the comments by Michael, Pedro and Sixseven on the “how many hours…” post taught me how to think out of box to solve a tricky problem like this with an elegant, simple formula. Thank you very much Michael, Pedro, Sixseven and each and every one of you who comment. 🙂
Have a great weekend everyone.
PS: This weekend is my mom’s birthday, plus it is a minor festival in India. So I am going to eat sumptuously, party vigorously and relax carelessly. Next week is going to be big with launch of excel school 3.
PPS: While at it, you may want to sign up for excel school already. The free lesson offer will vanish on Wednesday.

















7 Responses to “Project Dashboard + Tweetboard = pure awesomeness!!!”
I would like to see actual hash-tagged DM tweets go out to the specific information consumers. That would be an interesting way to communicate the key daily data to interested parties.
A Twitter-like secure application like Yammer might be a good fit with this.
For example, how about daily tweets to selected user groups (secure) that would display sales, bookings, cash receipts, cash disbursed and a second version that would show the same info for MTD, QTD or YTD figures.
@Dan, it would be great. I did not taught about implementing it on this dashboard because twitter is blocked to the whole intranet here. However, there's a discussion here about how can we send these tweets to blackberries (probably through e-mail) automatically. (I'd like to see this implemented on a jabber restricted network as well, but here it'll probably not happen)
The wrap-up versions you mentioned doesn't apply to my particular scenario, but on a sales tweetboard it would be a great tool indeed - choosing who will receive which message according to hashtags. I'll think on something, thanks for the advice. 🙂
(Ah, btw, I'm Fernando... 🙂 )
@Dan: That is a fun idea. Instead of tightly integrating twitter functionality with a dashboard, i think it would be cool if we have a "tweet this" button that users can click after selecting a range of cells. We can easily show a dialog with the concatenated output of the selected cells and ask user to edit the text and eventually "send to twitter".
For eg. you can select the annual sales figure cell and click on "tweet this" button upon which a dialog will show the value. Then you can pre-pend it something like "DM @boss look at our sales this year: "
@Aires.. thanks once again.
Wow it looks really good. Not sure though how much the tweet facility would help in real world project management, but certainly having a dashboard on a project should be a key deliverable when learning how to manage a project
The other use of this is during the software development life cycle especially when you have parallel streams of development and testing going on. Using a dashboard is a quick way for everyone on the team to see where the project is at and how it all fits together.
Regards
Susan de Sousa
Site Editor http://www.my-project-management-expert.com
Hi Chandoo,
I purchased the project management toolkit but the dashboard shown above with the imbedded scroll bars. Is it included in the project pack??
Thanks
Sue
The gantt chart section of this dashboard is similar to one I have recently created: http://xlcalibre.com/hr-dashboard-gantt-chart-traffic-light-reportIt has a similar approach with scroll bars, but has a couple of additional features. I've tried to incorporate a traffic light report element, and also allow the timescale to adjusted so that can view it by days, weeks or months.I really like the other tables that you've incorporated, I may well try to replicate them to improve my version!
I am a monitoring and evaluation consultant in international development, and one of the services I offer is to help non-profits and foundations develop performance dashboards. I often advise them to develop dashboards for ongoing programs, rather than for one-time or pilot projects, because of the time involved. I am trying to find out from a few people how long it takes you to develop a project management dashboard, and to what extent the indicators vary from one project to the next.