Use a colon to separate the parts of a time that you type in Excel. If you type 1:30:00, Excel recognizes information in that form as a time and stores it as decimal number 0.063136574. If you aren't keeping track of seconds, you can just type 1:30, which is stored as 0.0625.
To enter a time based on the 12-hour clock (instead of the 24-hour clock), type a space and then a or p after the time; for example, 9:00 p. If you do not type "a" or "p", Excel enters the time as AM. Excel stores 9:00 AM as 0.375 and 9:00 PM as 0.875.
You can select formats for times if you click Cells on the Format menu to open the Format Cells dialog box shown here.
Note You can see how Excel interprets information in a cell by selecting that cell and looking at the formula bar near the top of the worksheet. For example, if a cell contained 9:00, the formula bar would display 9:00:00 AM.