**A running total is a very useful mathematical operation that is simple to build in Excel** 👌

## When to do a running total?

A running total allows you to accumulate numerical data in order to show the evolution of a trend. In the following image, you have the sales (column B) and the running total of the sales in a store month by month (column C).

## Step 1: The first formula is different from the other

To make a running total, t**here is a difference between the first formula and the others**. The formula for the first cell is straightforward. Recall the reference to the first cell in our series.

## Step 2: Write the other formulas

To calculate **the cumulative amount of January and February, all** you have to do is add up the February turnover (in B3) with the previous cumulative amount (i.e. C2). The formula in C3 is then written

## Step 3: Copy of the formula

It only remains now to copy this formula for the rest of the document.

But beware, with **a "classic" copy** to the fill-handle, **you will destroy the format** of your document. To copy only the formulas, it's better to use the special collage in formula (opens in a new tab) the paste special (option formula) or right-click when copying, then select "Fill Without Formatting"

## Why does it work?

In fact, all the references in our cells are relative references. That is to say that the references will follow the direction of the copying. As you can see, the row's references have been increased by one automatically.

There are other situations where you must build a formula where **the references don't move** when copying a formula. **These are called absolute references** and are characterized by the appearance of the symbol $. This is the case when calculating** VAT**.

## Another technique: Block only one reference of the range.

With the SUM function, it's possible to create a running total by blocking only a part of the cell range.

### Construction of the formula

- Write a
**SUM function** - Block the
**first reference ONLY** **Keep the second reference**without dollar**=SUM($A$2:A2)**- Copy-Paste the formula

### Explanation of references

- By copying down, the first reference always remains in A2 (
**absolute reference with the $**). - Then, the copy progressively increases the reference of the second cells.
- Thus the parameters of the Sum function always correspond to the
*n*preceding cells.

**This method uses many** system resources 😤😤😤 In fact, you recalculate each cell for each new calculation. For instance, cell A2 was used 10 times in our previous calculation. This is not the best way to optimize a spreadsheet.