Let's say you want to calculate an extremely small tolerance level for a machined part or the vast distance between two galaxies. To raise a number to a power, use the "^" operator or the POWER function.
Example
The example may be easier to understand if you copy it to a blank worksheet.
How to copy an example
 Create a blank workbook or worksheet.
 Select the example in the Help topic.
Note Do not select the row or column headers.
Selecting an example from Help
 Press CTRL+C.
 In the worksheet, select cell A1, and press CTRL+V.
 To switch between viewing the results and viewing the formulas that return the results, press CTRL+` (grave accent), or on the Formulas tab, in the Formula Auditing group, click the Show Formulas button.

A 
B 
Formula 
Description (Result) 
=POWER(5,2) 
Calculates five squared (25) 
=5^3 
Calculates five cubed (125) 

Function details
POWER