Auto Fill using a formula

Hello there. You could use an IF formula. The solution there being you can set the false condition to equal a null string ("") which looks blank. To Excel there is a value in there, it's a zero length string, which can be confusing at first. There are inherent problems with that, however. First, since Excel see's it as having data (assuming the cells are blank), it will still print that range, because Excel thinks it has data - which it does, it's just an empty string, but it's a value nonetheless. Second, if your formula never meets the false condition, how are you to know you copied down the formula far enough? This regularly gets users as many data sets you don't know how long it will go down and often the solution is "copy it down really, really, really far *just in case* you need that many rows". As you could imagine this has some caveats.

The best case scenario is for you to define your data set, how and why it will do what it will do, and what the end goal is for it. I'm not sure what a solution would be because you haven't defined it very well at the moment but I can tell you it wouldn't be copying down an IF formula. Define your data more for us and we'll help you get a solution.