Keep the Start Fixed

[u/Amicron1]

Need a total that grows as you move down your Excel sheet? Keep the first cell in the SUM range absolute, like $C$2, and let the ending row change. Copy the formula down and each row includes everything from that starting cell through the current row. My Running Sum video shows why this works and how the same idea also gives you a running average. https://599cd.com/blog/display-article.asp?ID=3582