Page 285 - Excel 2007 Bible

18_044039 ch13.qxp 11/21/06 11:05 AM Page 242
Part II
Working with Formulas and Functions
Displaying the current time
This formula displays the current time as a time serial number (or as a serial number without an associated
date):
=NOW()-TODAY()
You need to format the cell with a time format to view the result as a recognizable time. The quickest way is
to choose Home ➪ Number ➪ Format Number and select Time from the drop-down list.
This formula is updated only when the worksheet is calculated.
NOTE
NOTE
To enter a time stamp (that doesn’t change) into a cell, press Ctrl+Shift+: (colon).
TIP
TIP
Displaying any time
One way to enter a time value into a cell is to just type it, making sure that you include at least one colon
(:). You can also create a time by using the TIME function. For example, the following formula returns a
time comprised of the hour in cell A1, the minute in cell B1, and the second in cell C1:
=TIME(A1,B1,C1)
Like the DATE function, the TIME function accepts invalid arguments and adjusts the result accordingly.
For example, the following formula uses 80 as the minute argument and returns 10:20:15 AM. The 80 min-
utes are simply added to the hour, with 20 minutes remaining.
=TIME(9,80,15)
CAUTION If you enter a value greater than 24 as the first argument for the TIME function, the result may
CAUTION
not be what you expect. Logically, a formula such as the one that follows should produce a
date/time serial number of 1.041667 (that is, one day and one hour).
=TIME(25,0,0)
In fact, this formula is equivalent to the following:
=TIME(1,0,0)
You can also use the DATE function along with the TIME function in a single cell. The formula that follows
generates a date and time with a serial number of 39420.7708333333 — which represents 6:30 PM on
December 4, 2007:
=DATE(2007,12,4)+TIME(18,30,0)
The TIMEVALUE function converts a text string that looks like a time into a time serial number. This for-
mula returns 0.2395833333, the time serial number for 5:45 AM:
=TIMEVALUE(“5:45 am”)
To view the result of this formula as a time, you need to apply number formatting to the cell. The
TIMEVALUE function doesn’t recognize all common time formats. For example, the following formula
returns an error because Excel doesn’t like the periods in “a.m.”
=TIMEVALUE(“5:45 a.m.”)
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