Returns the decimal number of the time represented by a text string. The decimal number is a value ranging from 0 (zero) to 0.99999999, representing the times from 0:00:00 (12:00:00 AM) to 23:59:59 (11:59:59 P.M.).
Syntax
TIMEVALUE(time_text)
Time_text is a text string that represents a time in any one of the Microsoft Excel time formats; for example, "6:45 PM" and "18:45" text strings within quotation marks that represent time.
Remarks
 Date information in time_text is ignored.
 Excel for Windows and Excel for the Macintosh use different date systems as their default. Time values are a portion of a date value and represented by a decimal number (for example, 12:00 PM is represented as 0.5 because it is half of a day).
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) 
=TIMEVALUE("2:24 AM") 
Decimal part of a day, for the time (0.1) 
=TIMEVALUE("22Aug2008 6:35 AM") 
Decimal part of a day, for the time (0.274305556) 

Note To view the number as a time, select the cell, and then on the Sheet tab, in the Number group, click the arrow next to Number Format, and click Time.