Often, when you enter numbers into a spreadsheet, you need to ensure that the number format is consistent. For example, if these numbers are prices, you may want to display the currency symbol or you may simply want to specify that the number of decimals displayed is always two.

Unless the user specifies otherwise, all numbers in Excel are rendered in the “General” format. What this means is that numbers are displayed exactly as one enters them: if you enter two decimals, two decimals are displayed; if you went to one decimal, one decimal is displayed; and so forth.

To specify the number format, the best idea is usually to select the entire column. To do this, simply click on the letter or letters representing the column. (If text is contained in the selection, it will not be affected by the number format you specify.)

Number formats are specified in the “Numbers” group of the Home Tab of Excel’s Ribbon. There are three important formats which apply to numbers: the first is simply called “Number”, the second “Currency” and the third “Accounting”. To gain access to the complete range of number formats, click on “More Number Formats” in the “Numbers” drop-down menu. Another way of opening the “Numbers” dialog box is to click on the launch button in the “Numbers” group of the Home Tab of the Excel Ribbon.

When you click on one of the number formats on the left of the “Numbers” dialogue box, you are given a series of choices which enable you to refine the way that the format will work. Thus, if your numbers refer to an hourly rate, you would click the “Number” category in the left column and then specify two decimal places. The option to “Use Thousands Separator” will add the appropriate separator to demarcate thousands. The separator used will depend on your locality: for example, in the UK or USA, a comma will be used; in European countries, a dot will be used.

The final option in the “Number” category lets you control the display of negative numbers. The default is to preced the number with a minus sign and to leave the colour of the text unchanged. However, you can also suppress the minus sign and change the colour of negative numbers to red; or, if you prefer, you can change the colour of negative numbers to red as well as displaying the minus sign.

When you click on the “Currency” category, you have pretty much the same choices with the addition of a currency symbol. One can specify which currency symbol is used or one can dispense with the currency symbol altogether.

The “Accounting” category is pretty much the same as “Currency”. Once again, you can choose a particular currency symbol. However, you will notice that you do not have any choices relating to negative numbers. The convention in accountancy circles is to always place negative numbers in brackets.

In addition to using the number dialog box, you’ll notice that there are a series of handy buttons which can apply each of the appropriate formats with one click. There are also two buttons for increasing and decreasing the number of decimals displayed in the selected numbers.

Finally, there will be times where you enter a number into a cell but do not want Excel to regard it as a number. For example, if you have a column of data with an ID of some sort, although the ID may be numeric, you may not want Excel to see it as a number or to change it in any way. You will probably want the ID to simply stay exactly as it was entered. In this scenario, it’s best to format the number as “Text”. The easiest way of doing this is to highlight the appropriate column and in the number dialog box select the “Text” category.