Total( ) function is used to get sum of region, while Sum( ) is used to get cumulative sum for a column.

In Origin 2025b, when sum() function is used in cell formula, it will get the total of the region. E.g. sum(A1:A10), sum(A1:D1), sum(A1:D10), sum(A1:B1, E1:F1).

Note: sum(A1:B1, E1) not supported still.