I am not sure if I knew this one before but it's a simple trick if all your zip code data is only 5 numbers in length. Warning it does not work if you have the extra digits in your zip code with a - in it.
So lets say your zip code is 04567, you likely know if Excel it will be turned into 4567. Well you can use the text function to fix that problem.
So lets say your zip code is in cell A1, your formula would be =text(A1,"00000")
And now it will change from 4567 to 04567.
I'll see if I can find a friends Excel code to fix it when you have all sorts of issues. It's a formula you will want to use if you have all sorts of problems with zip codes. I am taking about 20 hours of Excel training so I am sure I'll find some more nuggets to share on this blog. Stay tuned.