# Create a 'Red Alert' in Excel with Conditional Formatting

Updated on September 17, 2013

To those of a not-so-techy disposition, the term conditional formatting, as used in Microsoft Excel, sounds daunting. Yet it is an easy to understand, and genuinely useful function, and getting to grips with it is a good way for beginners to move their Excel skills up a notch.

Using an imaginary scenario to demonstrate conditional formatting, let us take the case of Barney, who runs a small business delivering sandwiches to local offices. Barney’s customers square up with him at the end of the week, and he enters the takings into an Excel sheet every Friday night. His customers are often out at meetings, or otherwise absent, and this is reflected in fluctuations in his takings. Sometimes Barney does not bring in enough money to cover his outgoings.

To make sure he always knows when this happens, Barney uses conditional formatting to give him a ‘red alert’ if his outgoings exceed his income. What this means is that the cell displaying his total income after bills have been paid will turn red if the value slips below zero.

The graphic above shows Barney’s Excel sheet before he has made any entries: column D is for his income, column E lists the bills he is paying, and column F shows those amounts. If you would like to follow this process, set up your Excel sheet exactly as I have done in the graphic (you needn’t bother with colouring the columns).

## A Simple Formula

The first step is to apply AutoSum to columns D and F so that your income and outgoings are totted up. An easy way to do this is to type a few random values into column D, select the group of cells from D5 to D28, and click on the AutoSum icon, which is in the form of the Greek Capital letter Sigma (Σ.). AutoSum will add up the values you entered, and the total will appear in cell D28. Delete your random values, and your cell will show a zero. Now any values you enter in that column will be added up, and the total shown in cell D28. Do exactly the same with column F, and you should have a pair of zeroes on display, as in the graphic above.

The next step is to format the cell G28, so that the total of column E is deducted from the total of column D. To do this, select cell G28, and enter the following formula, either directly into the cell, or in the formula bar:

=D28-F28

Test your formula by inserting random values into columns D and F. The value in cell G28 should change every time you enter or delete values in the other columns. Try a simple subtraction to be sure your formula is correct – enter 100 in column D, and 75 in column F If cell G28 shows 25, then, you are ready to apply conditional formatting.

## The Formatting

Go to the Conditional Formatting command on the Home tab. Click on Highlight Cells Rules, and select Less Than. In the Format cells that are LESS THAN box, type 0. The formatting you select will now be applied every time cell G28 shows a value below zero.

To select the type of formatting you wish to apply, click on the down arrow of the box that stands to the right of the word ‘with’, and a list of options will drop down. You could choose a combination of fill and text from this menu, but clicking on Custom Fill will allow you a much wider range of fills, font colours and styles. Click OK, and tinker with the values to see the cell change from green to red and back again.

You can take conditional formatting a step further by having the cell show as black when the value is above zero (and you are ‘in the black’). Doing this will leave only zero showing green (like a roulette wheel).

To format the cell for a second time, click on Conditional Formatting again, and add a second rule. When you click on Highlight Cells Rules this time, you will choose Greater Than. In the Format cells that are GREATER THAN box, type 0 again. The rest of the process is the same as above, but this time we opt for bold white text on a black background. Click OK, and the formatting is in place.

## Excel 2003

For those using earlier versions of Excel (2003 ), the process is slightly different.

Select cell G28 and go to Format, then Conditional Formatting. In Condition 1 choose Cell value is and Less Than, and enter 0. Then click on Format and select the Patterns tab. Select red from the choice of colours and click OK. As above, cell G28 is now formatted to turn red if the value within goes below zero. To format the cell for values above zero, open the Conditional Formatting menu, and click the Add button. From here the process is repeated as above.

This is a very basic example of conditional formatting, but it does, I hope, demonstrate how it works and when it can be used.

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