I am working on a sheet to deliver to some of our trading partners that needs an id number attached to the first column of the sheet. I have tried the formula =if(isblank(A2),"",<ID#>) to input the ID# (a hard coded numeric value, eg 56) into this first cell when the cell next to it is updated. However this inserts, by default, a NULL value into all 65K rows in the sheet as i need to copy and paste it down etc. Is there a way that i can get this value into the cell automatically when a value is entered (or pasted) into the A2 cell? I need to do this and not add any additional blank rows to the spreadsheet as this crashes an import downstream in the logic...