Dynamic if/then statement/vlookup formula.

[jdooley]

I have 1500 records that I need to assign new sub-ids. The sub-ids are located on sheet 2, cell A1 through A30.
*Only 50 records can be related to each unique sub-id.*

I hope use a formula that will insert the sub-id from sheet2 cell A1 in sheet 1 cell C1-C50, Sheet2 Cell A2 in Sheet1 cell C51-C100 etc...
Basically, I need the formula to insert the next sud-id after every 50 rows.

[PaulM100]

Try this in C2: =INDEX('Sheet2'!$A$1:$A$30,ROUNDUP(ROW()/50,0))

[jdooley]

that worked perfectly. If you don't mind will explain how the function works. I am always interested in the how and why?

[PaulM100]

Row function takes the first value found in Index and divides it by 50, meaning that the first value found will be added to first rows, and then it takes the second one and add it for next 50 rows, and so on.