WORKDAY Function is adding an extra day to my end date

[STCKNB1993]

Hello, 

I am trying to use the WORKDAY function to add X amount of days to my start date, however it is populating an extra day but only if I include the time. I don't need to include the time but its the only way I can get the project "duration" to show up on the calendar or timeline view. Can anyone help please? I've tried to add -1 days to remove a day from the start day but it is telling me there is an error. 

Current Formula: WORKDAY({Start Date}, {# of Days})

Thank you, 

[Sho]

Hello @STCKNB1993 ,

If "-1" is a number, it should be fine.
Is the value of "{# of Days}" a string?

If formulas are available. Try using the VALUE function.

[STCKNB1993]

# of Days is just a number