Essential Excel Formulas and Functions

Formulas are one of the key components of an Excel worksheet; this is, after all what makes Excel so useful; the fact that it can perform calculations on the data that you enter in your worksheets. In this video, we examine the key elements that can be included in a formula by entering the formulas required to create an invoice template.

In the last video, we saw how you can create a formula once and then copy it into other cells; and have Excel automatically modify the formula, based on the new location. In this video, we'll get some more practice on doing that and discuss, in a bit more depth, exactly how Excel arrives at the correct conclusions.

In this video, we'll look at an occasion where it is not useful to have Excel modify cell references when a formula is copied; and how you can tell Excel which cell references should not be changed when you copy a formula.

Having examined relative and absolute references, in this video, we'll look at  a third type of reference called mixed references. With mixed references, when you copy the formula, you want only one component to change; either the column letter or the row number, but not both.

As well as using parentheses to enclose function arguments, Excel uses parentheses in another context; and this usage coincides exactly with the use of parentheses in mathematics: to indicate the order of precedence when carrying out calculations.

Almost all Excel formulas contain cell references; and, if you are building a worksheet that contains a lot of formulas, it can become quite difficult to make sense of the worksheet formulas. One way to introduce a bit of clarity into your formulas is to use named ranges.

Very often, if all you want to do is to clean up data, or to modify the way that has been entered, you can simply use Flash Fill as an alternative to using formulas.

The TRIM function is a very simple but useful function which removes unwanted space from cell entries; and it is typically used when you are cleaning up text before producing a report.

Excel has three functions for changing the case of your text, two of which you should be able to guess with no problem: LOWER and UPPER, which of course correspond to upper and lower case. The third one is PROPER; this is what is sometimes called title case, whereby the first letter of each word is capitalized.

The LEFT and RIGHT functions are used, in Excel, to extract information, starting from the left or starting from the right.

The MID function is used to extract characters from a string of text, starting from any position. In this example, we have a customer code and we want to extract the two-letter country code in the middle of the string.

Excel's CONCATENATE function allows you assemble different textual components into one cell by stringing them together. In this example, we are starting with three separate columns containing "Title", "First Name" and "Last Name"; and we are looking to assemble them into a single cell; and this is exactly what CONCATENATE does.

The IF function in Excel is used to make the value in a cell dependent on the result of a logical test; a logical test being one which can only produce the values true or false.

The IF function is very versatile in Excel; by contrast, IFERROR has a very limited usage: its role is to suppress error values and replace them with something more user-friendly.

In the first video of this section, we had a look at a basic IF statement; sometimes, however, you want to cater for more than two eventualities; and, in this scenario, one approach is to use what is called a nested IF statement. This is where you use more than one IF statement; and Excel requires you to put one IF statement inside another, as its argument.

Excel's OR function is used to create a composite logical test; one in which you have a series of possibilities, only one of which needs to be true in order for the overall test to be true.

The AND function in Excel is used to create a composite logical test in which several possibilities all have to be true in order for the overall test to be true.

Excel's COUNTIF function is used to count the cells within a given range in which a certain condition is satisfied. It also has a "partner in crime", COUNTIFS, which does exactly the same thing, but allows you to specify two or more criteria.

The SUMIF function is obviously a combination of the SUM and IF functions; it allows you to calculate a conditional total.

Excel VLOOKUP function is used to retrieve a value from what is called a lookup table. In this example we use VLOOKUP to retrieve the business sector description which matches a given sector code.

As well as retrieving information by making a specific match to a given value, the VLOOKUP function can be used to retrieve information by making an approximate match.

Using the INDEX and MATCH functions in combination provides a great deal of flexibility when retrieving information from an ordinary worksheet, as opposed to a specially constructed lookup table.

In this video, we examine the key features of the completed template.

We begin by entering formulas to calculate line totals, sub-totals, VAT and grand total.

In this video, we take a break from creating formulas and create a drop-down list to display the names of all customers.

In this video, we use the VLOOKUP function, in conjunction with the concatenation operator, to pull in the address of the selected customer.

The CHAR function can be used to insert non-alphanumeric characters into a cell. In this video, we use it to insert line breaks after each line of the customer address.

As it stands, if the VLOOKUP function returns a null, our formula will insert a blank address line. In this video, we use an IF statement to prevent blank lines from being generated.

In this video, we protect the invoice worksheet; so that users can only enter values in cells which do not contain formulas.

We end this project by saving our invoice model as an Excel template.