title: Creating Unique ID with Sequential Numbers in Excel
body: <p>I found what I thought would help me create a unique ID for each row of data in an Excel spreadsheet.
  <img src="https://i.stack.imgur.com/6dSC1.png" alt="PIC of Sheet"> </p>
  
  <p>Ideally, I would like to automate this with maybe VBA and a button or trigger of some sort, but I could start with just a formula. I have rows of data with the first cell being the group number.  Then each row of data within each group is unique.  The problem is I need to assign a basic ID to each row starting with 1 and up to however many are in the group.  The data is dynamic and constantly changing, so each time changes are made, I need to filter out the group and manually fill down the numbers.  I found this formula (returning the number value in column D but looking for group numbers in A), but it does not work.</p>
  
  <p>=IF(A2="1",1+MAX($D$1:D1),"")</p>
  
  <p>Is there another way? Different function?  </p>