---
title: "3-Minute Win: Use SCAN to Add a Running Total Column Without Any Helper Columns"
date: 2026-05-09
updated: 2026-06-27T11:13:15Z
tags: ["DAX", "Excel", "Dynamic Arrays", "Efficiency", "Microsoft 365"]
canonical: https://bianca.codes/blog/3-minute-win-use-scan-to-add-a-running-total-column-without-any-helper-columns/
---

# 3-Minute Win: Use SCAN to Add a Running Total Column Without Any Helper Columns

_SCAN hands you every intermediate result as it accumulates — which means a running total is one formula that spills down the column. No helper rows, no dragging, no breaking when someone inserts a …_

Running totals used to mean dragging a formula down, or using a clunky `=SUM($B$2:B2)` that breaks the moment someone inserts a row. SCAN ends that. One formula at the top of the column, the result spills down, and the column updates itself when rows change.

## How to do it

You've got a table with a column of amounts in B2:B20. You want a running total in column C.

1. Click cell C2.
2. Type: `=SCAN(0, B2:B20, LAMBDA(acc, val, acc + val))`
3. Press Enter.

That's it. The running total spills from C2 to C20.

What happened: SCAN took a starting value of 0, ran through every value in B2:B20, and at each step added the current value to the accumulator. It returns every intermediate result, not only the final one. So C2 is 0 + first value, C3 is the previous total plus the second value, and so on down the column.

## Why it works

The LAMBDA is the rule for how to combine the running total so far (`acc`) with the next value (`val`). SCAN applies that rule iteratively and hands back the full sequence of intermediate accumulations. No helper column, no copy-down, no anchored references that need babysitting.

If the source range is in a structured table, point SCAN at the table column reference instead: `=SCAN(0, Transactions[Amount], LAMBDA(acc, val, acc + val))`. The running total automatically extends as new rows are added.

## When not to use it

If you need the running total _inside_ the same table as a column (so it survives sorting and filtering as a per-row value), SCAN won't work - the spill is a single block of cells, not table-aware. For that case you want a calculated column in Power Query or a measure in Power Pivot, not SCAN