Stop random numbers when Calculating, if field is blank

[MBML]

Hi
I have two columns A1 and B1. A1 I can enter a date into the other one has a formula that calculates and enter the new date for example =A1+20. If A1 is blank however how can I stop the B2 column with the formula in from showing a random date

 

[erik.van.geit]

Hello, MBLM,

you posted in the wrong forum
this thread will probably be moved to Excel-forum

do you need something like
=IF(A="","",A1+20)

kind regards,
Erik