I need to calculate the percent of time used similar to the "Networkdays" function in Excel. I thought i had the calculation correct until negative numbers popped up. How do i nest another If Statement if my Testing Start Date is greater than Today? Or better yet, less than 0? I'm doing something simple wrong with prins in the wrong place. Is my formula even RIGHT???

Phase Start Date = 7/15/15

Phase End Date = 9/30/15

Testing Start Date = 8/25/15

So, if today is 8/11/15, using the dates above, i've used 36% of my time. 20 workdays between 7/15 and 8/11....and there are 55 total workdays between 7/15 and 9/30.

My formula is below.

If([Daily NET Planned TCs]=0,0,1-(WeekdaySub([Phase End Date],Today()))/WeekdaySub([Phase End Date],[Testing Start Date]))

Thank you in advance!!