I am trying to work out a formula to display a second date if a date is entered into a specific cell, but to leave it blank if nothing is entered.
In C2 we enter the date a participant has taken a break from our program, they have 28 days to return before they are exited, in D2 I want to calculate the date of the last day they can return.
=C2+28 works fine for displaying the end date, but when dragged down returns 28/01/1900 when there is no date entered in C2, which makes for a confusing spreadsheet
I need a formula that will only return a date in D2 if C2 has a date entered


Any help really appreciated

You can try something like =IF(C2="","",C2+28) in D2, that looks to see if there is anything in C2 and if there isn't it clears the cell. However if they put something in there that isn't a date you'll get #VALUE!. To prevent this, if the only thing you want in there is a date, you can click on C2, then click on data menu, then click Data Validation. A pop up should come up, set Allow: to "Date", Data to "greater than" and then Start Date to 1\1\2014 or what ever date you want. Now when someone puts something in there other than a date, they will get a popup that says the value they entered is not valid. they can retry, cancel or select help. If you put both of these together you should have what you're looking for.

Works perfectly, thank you.

I dont know why I have so much trouble with IF formulas

Glad to hear it!