Office 2007 Bible

Entering Dates and Times into Your Worksheets

Excel treats dates and times as special types of numeric values. Typically, these values are formatted so that they appear as dates or times because we humans find it far easier to understand these values when they appear in the correct format. If you work with dates and times, you need to understand Excel’s date and time system.

Entering date values

Excel handles dates by using a serial number system. The earliest date that Excel understands is January 1, 1900. This date has a serial number of 1. January 2, 1900, has a serial number of 2, and so on. This system makes it easy to deal with dates in formulas. For example, you can enter a formula to calculate the number of days between two dates.

Most of the time, you don’t have to be concerned with Excel’s serial number date system. You can simply enter a date in a familiar date format and Excel takes care of the details behind the scene.

For example, if you need to enter June 1, 2007, you can simply enter the date by typing June 1, 2007 (or use any of several different date formats). Excel interprets your entry and stores the value 39234, which is the date serial number for that date.

Note

The date examples in this book use the U.S. English system. Depending on your regional settings, entering a date in a format (such as June 1, 2007) may be interpreted as text rather than a date. In such a case, you need to enter the date in a format that corresponds to your regional date settings—for ...