How to change change formulas such that formula is based on Work Days rather than Days

Hi Excel Forum members,
I have a schedule that has formulas that calculate end dates based on the number of days (including weekends) that a task takes to complete. Entering in the number of days calculates the end date as well as the number of work days to finish the task. However, I want to do the opposite such that (with the same start and end dates, except cells C10 and C28 which should be Monday and Friday, respectively) entering in the number of work days spits out the number of days (including weekends) a task would take to complete. Would anyone have any suggestions on how to do this? Furthermore, regarding cells C10 and C28, would anyone know a formula that adds the next working day to a date rather than calendar day? Please see the attached sample spreadsheet.

Thanks!

Originally Posted by Richard Buttrey

Are you saying you want to derive the column D (Days) numbers using Columns B & C?

Thanks for responding. I want to derive Days using Start and End Dates, and Work Days, where Work Days is a number whereas Start and End dates are formula driven.

Originally Posted by PietBom

For such calculations you can use the functions: WORKDAY.INTL() and NETWORKDAY.INTL()
For your subtotals you can better use the function: SUBTOTAL(ref,range)
The enclosed example will make it clear, I hope.

This was helpful, thanks!