How to create a counter and reset when the value changes

Billie

I need a formula in the unique main counter column that will count the number of times a value in ID_Main appears.

You can disregard this. I looked and looked and wasn't asking the questions correctly. I then after posting I found this from Paul in 2020. It does exactly what I need. Thank you Paul.

="M" + COUNTIFS([Size Column]$1:[Size Column]@row, [Size Column]@row).

Genevieve P.

Wonderful! Yes, thank you @Paul Newcome - I love seeing how the content posted years ago is still helping resolve questions today. Brilliant.

Thanks for posting your solution, @Billie 🙂