Excel provides no direct way to display the ratio between two values. For example, assume cell A1 contains 3, and cell B1 contains 24. The ratio between these two values is 1:8.

Following is a formula, contributed by Douglas J. Roach, that displays the ratio between the values in cells A1 and B1:

=(LEFT(TEXT(A1/B1,"####/####"),FIND("/",TEXT(A1/B1,"####/####"))-1)&":"
&RIGHT(TEXT(A1/B1,"####/####"),LEN(TEXT(A1/B1,"####/####"))
-FIND("/",TEXT(A1/B1,"####/####"))))

The formula automatically reduces the "fraction" to the simplest form, and it allows up to four characters on either side of the colon.

Jerry Meng pointed out a much simpler formula that produces the same result, but does not have the four-character limit:

=A1/GCD(A1,B1)&":"&B1/GCD(A1,B1)

Jerry's formula uses the GCD function, which is available only when the Analysis Toolpak Add-In is installed.

Note: Be aware that the result of these formulas is actually a time value, not a fractional value. For example, the ratio of 1:8 is not the same as 1/8. Rather, it is represented internally as 1:08 am.

Excel's IF function provides some simple decision-making capability to a worksheet. The IF function accepts three arguments:

• The condition being evaluated (should result in either TRUE or FALSE)
• The value to display if the condition is TRUE
• The value to display if the condition is FALSE

The formula below, for example, returns 1 if cell A1 contains "A". If cell A1 does not contain "A", the formula returns an empty string.

=IF(A1="A",1,"")

For more decision-making power, you can "nest" IF functions within a formula. In other words, you can use an IF function as the second argument for an IF function. Here's an example:

=IF(A1="A",1,IF(A1="B",2,IF(A1="C",3,"")))

This formula checks cell A1. If it contains "A", the formula returns 1. If it doesn't contain "A", then the second argument is evaluated. The second argument contains another IF function that determines if A1 contains a "B". If so, the formula returns 2; if not, the formula evaluates the IF function contained in the second argument and checks to see if A1 contains "C". If so, it returns 3; otherwise, it returns an empty string.

Excel allows up to seven levels of nested IF functions. The formula below works correctly, but Excel will not allow you to nest the IF functions any deeper than this.

=IF(A1="A",1,IF(A1="B",2,IF(A1="C",3,IF(A1="D",4,
 IF(A1="E",5,IF(A1="F",6,IF(A1="G",7,IF(A1="H",8,""))))))))

The sections that follow present various ways to get around the limit of seven nested IF functions. Be aware that these techniques may not be appropriate for all situations.

Using a VLOOKUP formula

In many cases, you can avoid using IF functions and use a VLOOKUP function. This will require a separate table in your worksheet. In the figure below, the lookup table is in B1:C10. The formula in A2 is:

=VLOOKUP(A1,B1:C10,2)

Using defined names

Another way to overcome the nested IF function limit is to use named formulas. Chip Pearson describes this technique at his web site, so I won't repeat it here.

• Nested Functions, at cpearson.com

Using the CONCATENATE function

Yet another option was suggested to me by B. Ganesh: Use the CONCATENATE function. In this case, each argument for CONCATENATE consists of an IF function. Here's an example:

=CONCATENATE(IF(A1="A",1,""),IF(A1="B",2,""),IF(A1="C",3,""),
IF(A1="D",4,""),IF(A1="E",5,""),IF(A1="F",6,""),IF(A1="G",7,""),
IF(A1="H",8,""),IF(A1="I",9,""),IF(A1="J",10,""))

The CONCATENATE function can handle as many as 30 arguments -- which equates to testing 30 different conditions.

And, as Alan Williams pointed out, you can avoid using the CONCATENATE function and use the concatenation operator (&):

   =IF(A1="A",1,"")&IF(A1="B",2,"")&IF(A1="C",3,"")
    &IF(A1="D",4,"")&IF(A1="E",5,"")&IF(A1="F",6,"")
   &IF(A1="G",7,"")&IF(A1="H",8,"")&IF(A1="I",9,"")
   &IF(A1="J",10,"")

This method is not limited to 30 comparisons.

Use Boolean multiplication

Another alternative, suggest by Daniel Filer is to use Boolean multiplication. This technique takes advantage of the fact that, when multiplying, TRUE is treated as 1 and FALSE is treated as 0. Here's an example:

=(A1="A")*1+(A1="B")*2+(A1="C")*3+(A1="D")*4+(A1="E")*5
+(A1="F")*6+(A1="G")*7+(A1="H")*8+(A1="I")*9+(A1="J")*10

Creating a custom VBA function

The final alternative is to create a custom worksheet function, using VBA. The advantage is that you can customize the function to meet your requirements, and your formulas can be simplified quite a bit.

This tip describes how to create what I call a "megaformula" -- a single formula that does the work of several intermediate formulas.

An Example

The goal is to create a formula that returns the string of characters following the final occurrence of a specified character. For example, consider the text string below (which happens to be a URL):

http://spreadsheetpage.com/index.php/tips

Excel does not provide a straightforward way to extract the characters following the final slash character (i.e., "tips") from this string. It is possible, however, do do so by using a number of intermediate formulas. The figure below shows a multi-formula solution. The original text is in cell A1. Formulas in A2:A6 are used to produce the desired result. The formulas are displayed in column B.

Following is a description of the intermediate formulas (which will eventually be combined into a single formula).

1. Count the number of slash characters (Cell A2)
   The formula in cell A2 returns the number of slash characters in cell A1. Excel doesn't provide a direct way to count specific characters in a cell, so this formula is relatively complex.
2. Replace the last slash character with an arbitrary character (Cell A3)
   The formula in A3 uses the SUBSTITUTE function to replace the last slash character (calculated in A2) with a new character. I chose CHAR(1) because there is little chance of this character actually appearing in the original text string.
3. Get the position of the new character (Cell A4)
   The formula in A4 uses the FIND function to determine the position of the new character.
4. Count the number of characters after the new character (Cell A5)
   The formula in A5 subtracts the position of the new character from the length of the original string. The result is the number of characters after the new character.
5. Get the text after the new character (Cell A6)
   The formula in A6 uses the RIGHT function to extract the characters -- the end result.

Combining the Five Formulas Into One

Next, these five formulas will be combined into a single formula.

1. Activate the cell that displays the final result (in this case, cell A6). Notice that it contains a reference to cell A5.
2. Activate cell A5. Press F2 and select the formula text (but omit the initial equal sign), and press Ctrl+C to copy the text. Press Esc.
3. Re-activate cell A6 and paste the copied text to replace the reference to cell A5. The formula in A6 is now:

=RIGHT(A1,LEN(A1)-A4)

4. The formula contains a reference to cell A4, so activate A4 and copy the formula as text. Then replace the reference to cell A4 with the copied formula text. The formula now looks like this:

RIGHT(A1,LEN(A1)-FIND(CHAR(1),A3))

5. Replace the reference to cell A3 with the formula text from cell A3. The formula now looks like this:

=RIGHT(A1,LEN(A1)-FIND(CHAR(1),SUBSTITUTE(A1,"/",CHAR(1),A2)))

6. Replace the reference to cell A2 with the formula text from cell A2. The formula now looks like this:

=RIGHT(A1,LEN(A1)-FIND(CHAR(1),SUBSTITUTE(A1,"/",CHAR(1),LEN(A1)-LEN(SUBSTITUTE(A1,"/","")))))

The formula now refers only to cell A1, and the intermediate formula are no longer necessary. This single formula does the work of five other formulas.

This general technique can be applied to other situations in which a final result uses several intermediate formulas.

NOTE: You may think that using such a complex formula would cause the worksheet to calculate more slowly. In fact, you may find just the opposite: Using a single formula in place of multiple formulas may speed up recalculation. Any calculation speed differences, however, will probably not be noticeable unless you have thousands of copies of the formula.

Caveat

Keep in mind that a complex formula such as this is virtually impossible to understand. Therefore, use this type of formula only when you are absolutely certain that it works correctly and you are sure that you will never need to modify it in the future. Better yet, keep a copy of those intermediate formulas -- just in case.

This tip describes a technique that should be in the arsenal of every Excel user. It describes how to use formulas to transform data.

The figure below shows a simple example. The text in column A consists of lower case letters. The goal is to transform these cells so they display "proper" case. This will be done by creating formulas that use Excel's PROPER function.

The steps below are specific to this example. But they can easily be adapted to other types of data transformations.

Creating the formulas

In this case, the formulas will go in column D. As you'll see, this is just a temporary location. The formula results will eventually replace the names in column A.

1. Enter the following formula in cell D2:

=PROPER(A2)

2. Copy the formula down the column to accommodate the data. In this case, the formula is copied down to cell D11. The worksheet now looks like this (the formula cells are selected, so they appear highlighted).

Copying and pasting the formula cells

In this step, the formula cells are copied, and pasted as values -- overwriting the original data in column A.

1. Select the formula cells. In this case, D2:D11.
2. Choose Edit - Copy
3. Select the first cell in the original data column (in this case, cell A2).
4. Choose Edit - Paste Special. This displays the Paste Special dialog box.
5. In the Paste Special dialog box, click the Value option button. This step is critical. It pastes the results of the formulas -- not the formulas.
6. Click OK.

At this point, the worksheet looks like this:

Deleting the temporary formulas

The formulas in column D are no longer necessary, so you can delete them.

Q. I have a range of time values, but when I try to sum them, the total is never greater than 24 hours.

When you add a range that contains time values, Excel ignores the hours that exceed 24. The solution is to use a custom number format.

1. Activate the cell that contains your total time
2. Choose Format, Cells.
3. In the Format Cells dialog box, click the Number tab.
4. Choose Custom from the Category list
5. Type [h]:mm into the box labeled Type.

Using brackets around the hour portion of the format string tells Excel to display hours that exceed 24 hours.

Q. I find that sometimes my formulas do not get fully calculated. This often happens when I use custom functions created with VBA.

Microsoft has acknowledged some problems with the Excel calculation engine in some version of Excel. In order to be assured that all of your formulas have been calculated, press Ctrl-Alt-F9 to force a complete recalculation.

This key combination will also update formulas that use custom VBA functions.

Q. Can I write a formula that returns the number of distinct entries in a range?

First, let's clarify the question. We're hunting for a formula that, given the range that contains the values 100, 99, 98, 100, 98, 100, 98, would return 3. In other words, this range contains three different values, some of them repeated.

This type of counting requires an array formula. The formula below, for example, counts the number of distinct entries in the range A1:D100.

=SUM(1/COUNTIF(A1:D100, A1:D100))

When you enter this formula, you must press Ctrl-Shift-Enter. Pressing only Enter will give you the wrong result. Excel will place brackets around the formula to remind you that you've created an array formula.

The preceding formula works fine in many cases, but it will return an error if the range contains any blank cells. The formula below (also an array formula, so input it with Ctrl-Shift-Enter) is more complex, but it will handle a range that contains a blank cell.

=SUM(IF(COUNTIF(A1:D100,A1:D100)=0, "", 1/COUNTIF(A1:D100,A1:D100)))