Late post to this thread; I created a custom workflow activity that will take two datetime values and determine the difference between them.  The activity will determine the difference in seconds, minutes, hours, days, business days, weeks, calendar weeks, months, quarters, and years.  The business days calculation uses the Workflow SDK to get the Workflow settings for Holidays and Weekends.  Here are some screenshots;

The custom activity will allow you to create multiple tokens.  In this case two tokens are created, one token called 'Days' to determine the number of days between 01/01/2015 and 03/31/2015 and the second token called 'Business Days' to determine the number of business days between those same dates...

This image shows an edit of the 'Business Days' token...

This image shows the results...

The DateDifference activity is available at www.qfiche.com as a free download.  (The download will install a 30-day trial activity.  When you register the activity I will provide a free production key.)

Caveat  - The activity has been tested on WF 9.1 and 9.2 but since I am accessing the Holiday and Weekend data via the Workflow SDK those function calls might change with future WF versions.  My intention though is to keep this activity current and tested on future releases as well.

Holidays can be added inside the Workflow Admin Console, so can be customized based on the customer needs and enable/disable/add the holidays you want to observe.  It is pretty slick.  My problem is that the "exclude Weekends and Holidays" option is only inside the Business Process Activites and even in that can't be passed a custom date to work with.

I was hoping to avoid a script.  It sure seems like it is built into Workflow as it appears in the Business Process Steps.  There just isn't an activity to do it for a normal workflow... yet.

Our workaround was to create a simple Access db and filled in the holidays from there.

Worked flawlessly.  We went Access so that the customer could easily edit holidays for their firm yearly as they are announced.  We essentially used Ken Salomon's tips above to create the workflow.  This customer also needed a date returned for different deadline requirements (14, 30, 60 working days), so we built the workflow to stand alone and be invoked by the other workflows.

These other workflows would pass the start date and business days as Inputs to the data calculation workflow and would get returned the formatted date excluding weekends and holidays.

Thanks Ken.  Your tips pointed me in the right direction.

Date Token Calculator does not have that feature.

Is there any way to do it without a script?

If a script is the only way, can anyone post one?

It would be great to have that as a new feature.

Ken - Interesting question.  I could see how you could determine the Weekends and exclude them from a date calculation but how would you determine Holidays? 

Would you be working from an internally maintained Holiday list or use something like a list of Federal Holidays?  Without going the self maintained list route you would have to jump through a bunch of calculations to determine the Holidays for any given date range.  If you go the Federal list of Holidays you would also have to determine which Holidays to include and which to exclude (as many businesses ignore some of the Federal Holidays).

Then also I assume that you are only concerned about US Holidays? 

Still, with all of that I think it might be do-able with some type of script activity or custom workflow activity but it would take quite a bit of work!

Ok, so if Workflow keeps track of it then I would think that the Holiday data might be in SQL somewhere.  Let me poke around a bit to see if I can find it. 

That would be ideal to have the feature added. 

I see in this post that it can be done but this will take time to implement, need to create a database for this and there is no real UI for data entry by the customer (we also need to build this UI).  Laserfiche should be offering this as there is already a Holiday/Weekend engine in the Workflow Admin Console and this feature is already available in some of the activities.  I really think that Laserfiche should be offering this.

I am mainly interested in getting a function where I can enter a Starting Date and an End Date, and the return value would be the number of working days between these two dates.

Can Laserfiche create that activity?

Is there any progress on this from the Laserfiche perspective as far as including this ability in the date token calculator?  The last post is pretty old.  I thought I heard that ver 10.2.1 might have the ability to use the date token calculator to "add" or adjust a given date by the number of "business days".  This is needed to calculate SLA's in a lot of business applications, where we need to calculate a "due date" for a process based on a number of business days since the process started.   Then we can trigger a message indicating processes that are due tomorrow or the next day, etc.

Thank you.  I am getting a formatting error.  Is there some special formatiing I need for the date?

See below:

I enter: WORKDAY(3/15/2017,4)

into the test formula and get this result.

 Invalid Date Value:  Function: WORKDAY Expression: WORKDAY(3/15/2017,4) Message: 0.000099157164105106593951413

I have tried several versions of the date and get the same result

Got it.  Boy, I would never have guessed that.  Should put that piece of information in the admin help files.  (Or at least I couldn't find it) 

Thanks for your help.

I know that this was posted a while ago, but I wanted to share my solution using date token calculator and conditional decisions for calculating observed holiday dates. We are observing federal holidays and I'm sure this could be modified to include/exclude other holidays.

https://answers.laserfiche.com/questions/181684/Calculate-Observed-Holidays-in-Workflow

I hope that it could be useful to someone.