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18_044039 ch13.qxp 11/21/06 11:05 AM Page 246
Part II
Working with Formulas and Functions
Converting from military time
Military time is expressed as a four-digit number from 0000 to 2359. For example, 1:00 AM is expressed as
0100 hours, and 3:30 PM is expressed as 1530 hours. The following formula converts such a number
(assumed to be in cell A1) to a standard time:
=TIMEVALUE(LEFT(A1,2)&”:”&RIGHT(A1,2))
The formula returns an incorrect result if the contents of cell A1 do not contain four digits. The following
formula corrects the problem, and it returns a valid time for any military time value from 0 to 2359:
=TIMEVALUE(LEFT(TEXT(A1,”0000”),2)&”:”&RIGHT(A1,2))
Following is a simpler formula that uses the TEXT function to return a formatted string, and then it uses the
TIMEVALUE function to express the result in terms of a time.
=TIMEVALUE(TEXT(A1,”00\:00”))
Converting decimal hours, minutes, or seconds to a time
To convert decimal hours to a time, divide the decimal hours by 24. For example, if cell A1 contains 9.25
(representing hours), this formula returns 09:15:00 (nine hours, 15 minutes):
=A1/24
To convert decimal minutes to a time, divide the decimal hours by 1,440 (the number of minutes in a day).
For example, if cell A1 contains 500 (representing minutes), the following formula returns 08:20:00 (eight
hours, 20 minutes):
=A1/1440
To convert decimal seconds to a time, divide the decimal hours by 86,400 (the number of seconds in a
day). For example, if cell A1 contains 65,000 (representing seconds), the following formula returns
18:03:20 (18 hours, three minutes, and 20 seconds):
=A1/86400
Adding hours, minutes, or seconds to a time
You can use the TIME function to add any number of hours, minutes, or seconds to a time. For example,
assume that cell A1 contains a time. The following formula adds 2 hours and 30 minutes to that time and
displays the result:
=A1+TIME(2,30,0)
You can use the TIME function to fill a range of cells with incremental times. Figure 13.9 shows a work-
sheet with a series of times in 10-minute increments. Cell A1 contains a time that was entered directly. Cell
A2 contains the following formula, which copied down the column:
=A1+TIME(0,10,0)

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