How Excel Works with Dates

Excel considers dates as numbers. Each date is assigned a unique serial number. For example, the 27th September 1999 was date serial 36430. Fortunately, you don't need to know this but the fact that all dates have numerical values can be very useful. Windows uses the 1900 date system in which 1st January 1900 is date serial 1, 2nd January 1900 is date serial 2 and so on.

When you type a date into a cell, Excel shows you a date but is thinking of a number.

To find out the serial number of a date, select the cell containing the date then go to Format > Cells. Go to the Number tab and click General in the Category list. The date's serial number will appear in the Sample box on the right.

You can make use of these numbers in all sorts of ways. You can add a number to a date to give a date that number of days later (or subtract a number to get a date before), you can take one date from another to find out how many days in between. There are lots of ready-made date functions too.

Working Out a Person's Age

A person's age is the amount of time since they were born (I know you know that but the computer doesn't, and we have to start thinking like the computer). So, all we have to do is put today's date in one cell and the person's date of birth in another cell, then take their date of birth away from today and you get their age - right? Well, sort of... you get a number. Because you took a date serial from another date serial you get the number of days in between*[note]. It looks like this...

In this example the formula in cell A3 is:

=A1-A2

We need to convert this number of days into a number of years. Most years have 365 days but every fourth year has 366 days. So the average number of years is 365.25. Let's modify our formula...

In this example the formula in cell A3 is:

=(A1-A2)/365.25

Note the brackets around the first part of the formula. Brackets mean "Work out this bit first...". I've used them here to stop Excel trying to divide A2 by 365.25 before taking it away from A1. Excel formulas work do any multiplying and dividing before it does adding and subtracting, but anything in brackets gets done first.

Now we can see a number of years, but it's still not quite right. We are getting an accurate result but we don't really want to see the fraction. As a last refinement we'll wrap the whole thing inside an INT() function to give us a whole number (an integer). This is better than changing the number of decimal places displayed, which would risk some numbers being rounded up and giving an incorrect result. Here's the finished result...

In this example the formula in cell A3 is:

=INT((A1-A2)/365.25)

*Note: In fact, to start with, you get another date. Confused? Don't be... Excel is trying to help but has misunderstood what we need. In date calculations, the result cell gets automatically formatted the same way as the first cell in the formula. Because the first cell was formatted as a date Excel showed you the result as a date, although you wanted to see a number. Just reformat the cell manually by going to Format > Cells > General

How to Calculate Age Range From Birth Date in An Excel Spreadsheet

Ever wonder the exact age of someone? Not just how many years old the person is, but his age down to the very second? If so, this Excel activity is the perfect solution. By simply entering today's date, the birth date and a few simple functions, the program can calculate a person's age in years, months, days, hours and even seconds. Follow the steps and easily calculate the age range from any birth date in an Excel spreadsheet.

# Enter the date data. In cell A1, type in today's date. In cell A2, type in the person's birth date.

#Enter the formula to display the age in years. In cell A3, enter the following formula: "=(A1-A2)/365.25." Then click "Enter." The result displayed is the person's age in years.

#Type the formula to display the age in months. In cell A4, enter the formula "=A3*12" and click "Enter." The person's age in months will display.

#Enter the formula to display the age in days. In cell A5, enter the formula "=A3*365.25" and hit "Enter." The person's age in days will show.

#Type the formula to display the age in hours. In cell A6, enter "=A5*24" and click "Enter." The person's age in hours will display.

#To show the person's age in seconds, type the formula "=A6*60" into cell A7 and click "Enter." The number displayed is the person's age in seconds.

Read more: How to Calculate Age Range From Birth Date in An Excel Spreadsheet | eHow.com http://www.ehow.com/how_5071205_calculate-birth-date-excel-spreadsheet.html#ixzz18MF2DS00

Excel Charts

Creating Charts

In Microsoft Excel, you can represent numbers in a chart. On the Insert tab, you can choose from a variety of chart types, including column, line, pie, bar, area, and scatter. The basic procedure for creating a chart is the same no matter what type of chart you choose. As you change your data, your chart will automatically update.

You select a chart type by choosing an option from the Insert tab's Chart group. After you choose a chart type, such as column, line, or bar, you choose a chart sub-type. For example, after you choose Column Chart, you can choose to have your chart represented as a two-dimensional chart, a three-dimensional chart, a cylinder chart, a cone chart, or a pyramid chart. There are further sub-types within each of these categories. As you roll your mouse pointer over each option, Excel supplies a brief description of each chart sub-type.

Creating Charts

In Microsoft Excel, you can represent numbers in a chart. On the Insert tab, you can choose from a variety of chart types, including column, line, pie, bar, area, and scatter. The basic procedure for creating a chart is the same no matter what type of chart you choose. As you change your data, your chart will automatically Update. This lesson teaches you how to create a chart in Excel.

* Create a Chart
* Apply a Chart Layout
* Add Labels
* Switch Data
* Change the Style of a Chart
* Change the Size and Position of a Chart
* Move A Chart to a Chart Sheet
* Change the Chart Type

Creating Excel Functions, Filling Cells, and Printing

By using functions, you can quickly and easily make many useful calculations, such as finding an average, the highest number, the lowest number, and a count of the number of items in a list. Microsoft Excel has many functions you can use. You can also use Microsoft Excel to fill cells automatically with a series.For example, you can have Excel automatically fill your worksheet with days of the week, months of the year, years, or other types of series.

A header is text that appears at the top of every page of your printed worksheet. A footer is text that appears at the bottom of every page of your printed worksheet. You can use a header or footer to display among other things titles, page numbers, or logos. Once you have completed your Excel worksheet, you may want to print it. This lesson teaches you how to use functions, how to create a series, how to create headers and footers, and how to print.

* Using Reference Operators
* Understanding Functions
* Fill Cells Automatically
* Create Headers and Footers
* Set Print Options
* Print