In Excel, an array formula is a formula that carries out calculations on one or more elements in an array.

Array formulas in Excel are surrounded by curly braces "**{ }** ". These are added to a formula by pressing the **CTRL**+**SHIFT**+**ENTER** keys after typing the formula into a cell or cells.

## Types of Array Formulas

There are two types of array formulas - those that are located in multiple cells in a worksheet (multi-cell array formula) and those located in a single cell (single cell array formula).

## How a Single Cell Array Formula Works

A single cell array formula differs from regular Excel formulas in that it performs multiple calculations in one cell in a worksheet without the need for nesting functions.

Single cell array formulas normally first carry out a multi-cell array calculation — such as multiplication — and then use a function such as or AVERAGE or SUM to combine the output of the array into a single result.

In the image above the array formula first multiplies together those elements in the two ranges D1:D3 and E1:E3 that reside in the same row in the worksheet.

The results of these multiplication operations are then added together by the SUM function.

Another way of writing the above array formula would be:**(D1 * E1) + (D2 * E2) + (D3 * E3)**

## Entering the Tutorial Data

To begin the tutorial it is necessary to enter our data into an Excel worksheet as seen in the image above.

Cell Data

D1 - 2

D2 - 3

D3 - 6

E1 - 4

E2 - 5

E3 - 8

## Adding the SUM Function

The next step in creating the single cell array formula is to add the sum function to cell F1 — the location where the single cell array formula will be located.

## Tutorial Steps

For help with these steps see the image above.

- Click on cell F1 — this is where the single cell array formula will be located.
- Type an equal sign (
**=**) to begin the sum function. - Type the word
**sum**followed by a left round bracket**(**. - Drag select cells D1 to D3 to enter these cell references into the sum function.
- Type an asterisk symbol (
*****) since we are multiplying the data in column D by the data in column E. - Drag select cells E1 to E3 to enter these cell references into the function.
- Type a right round bracket
**)**to close the ranges that will be summed. - At this point, leave the worksheet as is — the formula will be completed in the last step of the tutorial when the array formula is created.

## Creating the Array Formula

The last step in the tutorial is turning the sum function located in cell F1 into an array formula.

Creating an array formula in Excel is done by pressing the **CTRL**+**SHIFT**+**ENTER** keys on the keyboard.

The effect of pressing these keys together is to surround the formula with curly braces: { } indicating that it is now an array formula.

## Tutorial Steps

For help with these steps see the image above.

- Hold down the
**CTRL**and**SHIFT**keys on the keyboard then press and release the**ENTER**key to create the array formula. - Release the
**CTRL**+**SHIFT**keys. - If done correctly cell F1 will contain the number "
**71**" as seen in the image above. - When you click on cell F1 the completed array formula
**{ =SUM (D1:D3 * E1:E3) }**appears in the formula bar above the worksheet.