A running total shows the total so far at every row, such as month-to-date sales or a bank balance. It only needs one small trick: a range that starts fixed and ends relative.
The basic formula
Sales in B2:B13. In C2 type:
=SUM($B$2:B2)
Copy it down. In C3 it becomes =SUM($B$2:B3), then =SUM($B$2:B4), and so on. The first cell stays locked and the last one moves.
A simpler version
Another option is =C2+B3 in C3, which adds the new amount to the previous total. Type =B2 in C2 to start. It works, but if you delete a row in the middle the chain breaks, so the SUM version is safer.
Restart the total for each category
With categories in A and amounts in B, use SUMIFS with the same expanding range:
=SUMIFS($B$2:B2, $A$2:A2, A2)
The total restarts for every new category.
Running balance
With deposits in B and withdrawals in C, balance in D2:
=SUM($B$2:B2)-SUM($C$2:C2)
Percentage of total so far
Divide the running total by the grand total: =C2/SUM($B$2:$B$13). Format as a percentage. This is the basis of a Pareto chart.
Common mistakes
- Forgetting the dollar signs, so the start of the range slides down with each row.
- Sorting the data after you build the formulas. A running total depends on the row order, so sort first.