Excel's Formula - sisman

146
Part II: Using Functions in Your Formulas
Table 6-1: Date Entry Formats Recognized by Excel (continued)
Entry Excel’s Interpretation (U.S. Settings) What Excel Displays
6/18 June 18 of the current year 18-Jun
6-18 June 18 of the current year 18-Jun
18-Jun-2010 June 18, 2010 18-Jun-10
2010/6/18 June 18, 2010 Windows short date
As you can see in Table 6-1, Excel is pretty good at recognizing dates entered into a cell. It’s not
perfect, however. For example, Excel does not recognize any of the following entries as dates:
June 18 2010
Jun-18 2010
Jun-18/2010
Rather, it interprets these entries as text. If you plan to use dates in formulas, make sure that
Excel can recognize the date that you enter as a date; otherwise, the formulas that refer to these
dates will produce incorrect results.
If you attempt to enter a date that lies outside of the supported date range, Excel interprets it as
text. If you attempt to format a serial number that lies outside of the supported range as a date,
the value displays as a series of hash marks (#########).
Understanding time serial numbers
When you need to work with time values, you simply extend Excel’s date serial number system
to include decimals. In other words, Excel works with times by using fractional days. For example,
the date serial number for June 18, 2010, is 40347. Noon (halfway through the day) is represented
internally as 40347.5.
The serial number equivalent of 1 minute is approximately 0.00069444. The formula that follows
calculates this number by multiplying 24 hours by 60 minutes and then dividing the result into 1.
The denominator consists of the number of minutes in a day (1,440).
=1/(24*60)
Searching for dates
If your worksheet uses many dates, you may need to search for a particular date by using Excel’s
Find dialog box (which you can access with the Home➜Editing➜Find & Select➜Find command,
or Ctrl+F). Excel is rather picky when it comes to finding dates. You must enter a full four-digit
year into the Find What field in the Find dialog box. The format must correspond to how dates
are displayed in the Formula bar.