In Excel, you can format numbers in cells for things like currency, percentages, decimals, dates, phone numbers, or social security numbers.

Select a cell or a cell range.

On the Home tab, select Number from the dropdown.
Or, you can choose one of these options:
Press CTRL + 1 and select Number.

Rightclick the cell or cell range, select Format Cells… , and select Number.

Select the dialog box launcher next to Number and then select Number.


Select the format you want.
Number formats
To see all available number formats, click the Dialog Box Launcher next to Number on the Home tab in the Number group.
Format  Description 

General 
The default number format that Excel applies when you type a number. For the most part, numbers that are formatted with the General format are displayed just the way you type them. However, if the cell is not wide enough to show the entire number, the General format rounds the numbers with decimals. The General number format also uses scientific (exponential) notation for large numbers (12 or more digits). 
Number 
Used for the general display of numbers. You can specify the number of decimal places that you want to use, whether you want to use a thousands separator, and how you want to display negative numbers. 
Currency 
Used for general monetary values and displays the default currency symbol with numbers. You can specify the number of decimal places that you want to use, whether you want to use a thousands separator, and how you want to display negative numbers. 
Accounting 
Also used for monetary values, but it aligns the currency symbols and decimal points of numbers in a column. 
Date 
Displays date and time serial numbers as date values, according to the type and locale (location) that you specify. Date formats that begin with an asterisk (*) respond to changes in regional date and time settings that are specified in Control Panel. Formats without an asterisk are not affected by Control Panel settings. 
Time 
Displays date and time serial numbers as time values, according to the type and locale (location) that you specify. Time formats that begin with an asterisk (*) respond to changes in regional date and time settings that are specified in Control Panel. Formats without an asterisk are not affected by Control Panel settings. 
Percentage 
Multiplies the cell value by 100 and displays the result with a percent (%) symbol. You can specify the number of decimal places that you want to use. 
Fraction 
Displays a number as a fraction, according to the type of fraction that you specify. 
Scientific 
Displays a number in exponential notation, replacing part of the number with E+n, where E (which stands for Exponent) multiplies the preceding number by 10 to the nth power. For example, a 2decimal Scientific format displays 12345678901 as 1.23E+10, which is 1.23 times 10 to the 10th power. You can specify the number of decimal places that you want to use. 
Text 
Treats the content of a cell as text and displays the content exactly as you type it, even when you type numbers. 
Special 
Displays a number as a postal code (ZIP Code), phone number, or Social Security number. 
Custom 
Allows you to modify a copy of an existing number format code. Use this format to create a custom number format that is added to the list of number format codes. You can add between 200 and 250 custom number formats, depending on the language version of Excel that is installed on your computer. For more information about custom formats, see Create or delete a custom number format. 
You can apply different formats to numbers to change how they appear. The formats only change how the numbers are displayed and don’t affect the values. For example, if you want a number to show as currency, you’d click the cell with the number value > Currency.
Applying a number format only changes how the number is displayed and doesn’t affect cell values that’s used to perform calculations. You can see the actual value in the formula bar.
Here’s a list of available number formats and how you can use them in Excel Online:
Number format  Description 

General 
Default number format. If the cell isn’t wide enough to show the entire number, this format rounds the number. For example, 25.76 shows as 26. Also, if the number is 12 or more digits, General format displays the value with scientific (exponential) notation.

Number 
Works very much like the General format but varies how it shows numbers with decimal place separators and negative numbers. Here are some examples of how both formats display numbers:

Currency 
Shows a monetary symbol with numbers. You can specify the number of decimal places with Increase Decimal or Decrease Decimal.

Accounting 
Also used for monetary values, but aligns the currency symbols and decimal points of numbers in a column. 
Short Date 
Shows date in this format:

Long Date 
Shows month, day and year in this format:

Time 
Shows number date and time serial numbers as time values. 
Percentage 
Multiplies the cell value by 100 and displays the result with a percent (%) symbol. Use Increase Decimal or Decrease Decimal to specify the number of decimal places you want.

Fraction 
Shows the number as a fraction. For example, 0.5 displays as ½. 
Scientific 
Displays numbers in exponential notation, replacing part of the number with E+n, where E (Exponent) multiplies the preceding number by 10 to the nth power. For example, a 2decimal Scientific format displays 12345678901 as 1.23E+10, which is 1.23 times 10 to the 10th power. To specify the number of decimal places you want to use, apply Increase Decimal or Decrease Decimal. 
Text 
Treats the cell value as text and displays it exactly as you type it, even when you type numbers. Learn more about formatting numbers as text. 
Need more help?
You can always ask an expert in the Excel Tech Community, get support in the Answers community, or suggest a new feature or improvement on Excel User Voice.