Calculations in Excel

Learn the 4 steps that make entering a calculation into an Excel spreadsheet work reliably every time.

Never entered a calculation into an Excel spreadsheet? When you’ve finished this short tutorial, you’ll be able to create formulas in Excel to make your business life just a little bit easier…

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We’re just getting started (this is our first video) so the resources available on the tekbites.com website will be quite limited to begin with – apologies in advance.

Percentage difference between two numbers in Excel

We served 2,800 customers last month and 3,200 customers this month. What percentage increase is that?

This calculation requires three steps.

First calculate the difference between the two numbers. Then, calculate this value as a ‘fraction’ of the earlier number. Finally ask Excel to display this result as a percentage.

The difference between the two numbers is always the later or more recent number minus the earlier or older number.

In the example below, customer numbers have increased from 2,800 last month to 3,200 this month. First, calculate the difference.

Next, take the difference between the two numbers and divide by the original number.

Finally, change the format of the answer so that Excel displays it as a percentage. This can be done using the percentage icon on the toolbar.

It is usually worthwhile increasing the number of decimal places displayed so that a more accurate value is shown.

Customer numbers changing from 2,800 to 3,200 represents an increase of 14.29%.

 

We served 3,500 customers last month and 3,400 customers this month. What percentage decrease is that?

Where the number decreases, the steps are the same.

In the example below, customer numbers have decreased from 3,500 last month to 3,400 this month. First, calculate the difference.

Here, the difference is a negative number, representing a decrease in numbers.

Next, take the difference between the two numbers and divide by the original number.

Finally, change the format of the answer so that Excel displays it as a percentage. This can be done using the percentage icon on the toolbar.

Again, it is usually worthwhile increasing the number of decimal places displayed so that a more accurate value is shown.

Customer numbers changing from 3,500 to 3,400 represents a decrease of 2.86%.

Try it yourself using the examples below…

Download this example

Download all percentage examples

What percentage does a value represent of the total amount?

7 answers out of 12 were correct. What is the percentage score?

This type of calculation is best approached as a fraction.

The partial value, in this case 7, is divided by the total value. Formatting is then used to display the resulting number as a percentage.

In the example below, 7 answers were correct out of a possible 12.

Finally, change the format of the answer so that Excel displays it as a percentage. This can be done using the percentage icon on the toolbar.

It is usually worthwhile increasing the number of decimal places displayed so that a more accurate value is shown.

A score of 7 correct out of 12 questions represents a total score of 58.33%.

Try it yourself using the examples below…

Download this example

Download all percentage examples

Decrease a number by a percentage

Calculate a discount of 9% on a purchase of 120

This is best approached in two stages.

First, calculate the percentage required using the technique described here – Finding a percentage of a number. Then subtract this amount from the original.

In the example below a 9% discount is applied to a purchase of 120.

If you get a 9% discount on a purchase of 120, you only pay 109.20.

Try it yourself using the examples below…

Download this example

Download all percentage examples

Using COUNTIF to count specific items in an area

How many of the items in this list are red?

The COUNTIF function can be used to count only certain specific entries in a list. It requires two pieces of information.

The area containing the items to be counted and some way to tell which entries are required.

In the example below, which was created in the UK in the dead of winter, the colours of the items to be counted are contained within the range C3 to C12

If only the red items are to be counted, these are identified using the word RED. To indicate that this is literally the word RED, the text must be enclosed within speech marks.

Please note that a text match of this type is not case sensitive.

To find out how many hats are in the list, a similar procedure is followed. The only difference is that the item type is listed in the range B3 to B12. Once again, the text criteria is enclosed in speech marks and it does not matter whether upper or lower case text is used.

And if you want to know how many red hats are in the list, click here

Try it yourself using the examples below…

Download this example

Download all counting examples

Count everything in an area

How many entries have been completed?

In the example below, an ‘x’ has been used to indicate who has shown an interest in a neighbourhood watch scheme. To find out how many people are interested, the COUNT function might be used.

COUNT, like all functions, has a set of brackets that contain the details of the area containing the items to be counted.

The screen shot below shows the result of using COUNT on the column containing the ‘x’ characters.

The COUNT function only ever counts numbers. Since ‘x’ is a text character, the result comes out as 0.

To count numbers, text and pretty much anything else, use the COUNTA function. You can think of the A as meaning All or Anything.

The screen shot below shows the result of using COUNTA on the same column.

If dates had been used instead of a text character, the COUNT function would have been fine since properly entered dates are numbers in Excel!

Try it yourself using the examples below…

Download this example

Download all counting examples

Counting stuff in Excel

The COUNT function is used in Excel to find out how many items appear in a specific area of the worksheet.

Unfortunately for the unwary, COUNT only works for numbers. To get the most out of this family of functions, you need to know about COUNTA and COUNTIF as well

Try these short tutorials – the easiest one is at the top…

Count everything in an area
(How many entries have been completed?)

Only count specific items in an area
(How many of the items in this list are red?)

Count using two criteria
(How many hats in this list are red?)

Percentages in Excel

The use of percentages in Excel are not the easiest concept to understand.

The percentages you use with Excel are just the same as the ones you might calculate with a calculator but it helps if you think about them slightly differently when calculating in Excel.

Always enter a percentage in Excel as a number followed by a percent sign. If you work this way, you don’t have to worry about all that multiplying and dividing by 100!

Try these short tutorials – the easier ones are at the top…

Percentage of a number

(What is 7% of 2,500?)

Increase a number by a percentage

(Increase 24,000 by 4%)

Decrease a number by a percentage

(Calculate a discount of 9% on a purchase of 120)

What percentage does a value represent of the total amount?

(7 answers out of 12 were correct. What is the percentage score?)

Difference between two numbers as a percentage

(Customer numbers changed from 2,800 to 3,200. What percentage increase is that?)
(Customer numbers changed from 3,500 to 3,400. What percentage decrease is that?)