vacation day formula - help

[Aly_Fossett]

I am having trouble with my vacation day calculation when an employee is only taking one day off. I have a formula to count the days requested and they always show up as negative which is what I want to subtract from their approved days, but when they request 1 day is comes up as a +1 and throws the calculation off. Could someone help me with this? I know it has to be a simple fix. Thanks! 

This is the formula I am using: 

WORKDAY_DIFF({End date (vacation)}, {Start date (vacation)})

[Databaser]

Try DATETIME_DIFF() instead. It will give 0.