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In Depth Information

**Chapter 16: Working with Dates and Times**

16

Working with Dates and Times

IN THIS CHAPTER

Getting an overview of dates and times in Excel

Using Excel date-related functions

Working with Excel time-related functions

Many worksheets contain dates and times in cells. For example, you might track information by

date or create a schedule based on time. Beginners often ﬁ nd that working with dates and times

in Excel can be frustrating. To work with dates and times, you need a good understanding of how

Excel handles time-based information. This chapter provides the information you need to create

powerful formulas that manipulate dates and times.

The dates in this chapter correspond to the U.S. English language date format: month/day/year. For example, the

date 3/1/1952 refers to March 1, 1952, not January 3, 1952. This setup may not seem illogical, but that’s the way

Americans have been trained. Non-American readers of this topic should make the adjustment, please.

How Excel Handles Dates and Times

This section presents a quick overview of how Excel deals with dates and times. It covers Excel’s

date and time serial number system. This section also provides some tips for entering and

formatting dates and times.

Understanding date serial numbers

To Excel, a date is simply a number. More precisely, a date is a
serial number
that represents the

number of days since the ﬁ ctitious date of January 0, 1900. A serial number of 1 corresponds to

January 1, 1900; a serial number of 2 corresponds to January 2, 1900; and so on. This system makes

it possible to create formulas that perform calculations with dates. For example, you can create a

formula to calculate the number of days between two dates (just subtract one from the other).