How to calculate percentages in Excel

Pubblicato il Autore Marco Lazzari

Many people land on my institutional site by looking for percentage calculation with Excel. And their needs, as resulting from their search keys, are rather simple to satisfy.
Therefore, I try to collect here some examples related the most common requests.
For each example, I propose a screenshot (public domain pictures, made by myself): the formula is highlighted in the formula bar.
Example 0 – (quickly, for those who really do not mean to think about it) should I want to calculate a given percentage of an amount, I can simply write a formula that multiplies the amount by the percentage. For instance I want to know the 19% of 2500, I set the cursor on a cell and write =2500*19% (or =2500*19/100; or simply =2500*19 and then I format the cell using the predefined percentage format)
Example 1 – I know the price of a product and I know that a certain discount has been applied (in the example: 15%): how much is the discount?

Example 2 – I know the price of a product and I know that I will benefit from a certain discount (in the example: 15%): how much will I spend?

Example 3 – I know the sale price of a product and I know its original retail price: what discount has been applied?

Example 4 – I know the cost of a product and I want to increase it by a certain percentage (in the example: 15%): what will be the final price?

Example 5 – I correctly answered a certain number of questions on a test (27 out of 40): how can I express this result as a percentage score?

Example 6 – How to deduct tax from a price which includes tax: I know the price of a product (gross price) and I know that a certain tax has been applied (in the example: 15%): how much is the price before tax (net price)?

Example 7 – political elections, four parties got valid votes, I know their votes and the total of valid votes, how do I calculate the percentage of each party? [in this case I have not multiplied by 100, the cell format did the dirty work; note the $ sign, to allow to copy and paste the formula]

P.S.: when I say Excel, I mean Calc as well; and also those bizarre versions of Excel that I regularly find within the log files of my sites, and which are used as search keys, such as Exel, Exell, Exelle, Excell, Excelle, Exelles, Excelles, …