How to calculate percentages in Excel step by step

To dominate How to calculate percentages in Excel It makes all the difference between struggling with a calculator and letting a spreadsheet do the hard work for you. From a simple "what is 12% of 200?" to calculating discounts, taxes, month-to-month variations, or what percentage of the total each piece of data represents, everything can be automated with a few very simple formulas.

Throughout this article you will see, step by step, All the practical ways to work with percentages in ExcelHow to enter them correctly, how to display the results with the % symbol, how to calculate the percentage of a number, how to find out what percentage a part of the total represents, how to calculate increases and decreases, discounts, VAT, income tax, and even how to recover the total value when you only know a discounted price and the percentage applied.

How Excel understands percentages and how to format them

Before you start writing formulas, it's key to understand How Excel interprets percentages internallyFor the program, a percentage is nothing more than a decimal number: 10% is 0,1; 25% is 0,25; 75% is 0,75 and 100% is 1.

When you apply the percentage format When you format a cell as a decimal, Excel simply displays that decimal multiplied by 100 and adds the % symbol. For example, if you have 0,1 in a cell and apply the % format, you'll see 10%; if you have 0,754, depending on your configured decimal settings, you'll see something like 75,4% or 75,40%.

If you already have numbers written and then apply the percentage format, Excel multiply those numbers by 100In other words, if a cell contains 10 and you format it as a percentage, the visual result will be 1000,00%. This often catches many people off guard because the logical thing to do for 10% would be to type 0,1 or to indicate that the cell was a percentage before entering the value.

However, if you first format an empty range as a percentage and then type in it, Excel It behaves differently depending on the numberIf you type 10 (equal to or greater than 1), it will display 10%; if you type 0,1 (less than 1), you will also see 10% because it multiplies it by 100 to display it as a percentage.

Therefore, to work well with percentages, it is important that the underlying value is correct: if you want 10%The cleanest way is to write 0,1 or 10 in a cell that already has the percentage format applied, and then let Excel display it correctly.

How to apply percentage formatting in Excel

To display your results with the % symbol, you need to apply the percentage format to the cells where you want to display those values. It's very quick to do this from the ribbon.

First, select the cell or range of cells that you want to format. Then, go to the “Home” tab and, within the “Number” group, click on the icon with the percent (%). Instantly, the values ​​will be displayed as percentages with the decimal places that are configured by default.

If you prefer to adjust the format in more detail, you can right-click on the selection and choose "Cell format"In the window that opens, choose "Percentage" from the list of categories and decide how many decimal places you want to display. For example, if you enter 0 in "Decimal places," you will see 10% instead of 10,00%.

You can also use shortcuts to go faster: in many versions of Excel, pressing Ctrl + Shift + % It instantly applies the percentage style to the selected range, without having to go through menus.

Keep in mind that, as we saw earlier, if you apply percentage formatting to cells that already contain numbers, Excel He does not interpret those numbers as percentages. magically; it simply multiplies them by 100 and adds the % symbol, so make sure your starting value is correct.

Calculate what percentage a part represents of the total

One of the most common operations is knowing What percentage does a quantity represent in relation to a total?Mathematically it is as simple as dividing the partial value by the total value and, if you want, multiplying by 100 to express the result as a percentage.

The general formula would be: percentage = (part / total)If you format that division as a percentage, you don't need to multiply by 100 because Excel will do it visually for you. If you're not going to format it, then it's best to write (part / total) * 100. If you need to review arithmetic operations in Excel, see Arithmetic operations in Excel.

Imagine a primary school class with 31 students, 17 of whom are girls. The partial value is the girls (17), and the total value is all the students (31). In a cell, you could write =17/31 and, after formatting it as a percentage, you would get approximately 54,8%This way you can fairly compare with other classes that have more or fewer students.

If you wanted to see the calculation without using reference cells, you could type directly into a cell: =17/31*100In this case, the result would be 54,8 without the % symbol, since you did the multiplication by 100.

This same approach is useful for questions like “what percentage does it represent = 7 / 30“?” (for example, apples taken from a total in a jar) or “what percentage of the class passed?”. Simply type =7/30 into a cell, apply percentage formatting, and you will get the exact percentage.

Calculate the percentage of an amount

The other basic case is the reverse: you want to know What is a specific percentage of a number?For example, what amount is equivalent to 12% of 200 or 40% of 340? Here the operation is very straightforward: simply multiply the total by the percentage in decimal form.

The generic formula would be: value = total * percentageIf you have the total in one cell and the percentage in another, the normal practice is to use cell references. For example, if the total is in D2 and the percentage is in E2, the formula would be =D2*E2.

Imagine you want to know 12% of 200. You can write in a cell: =200*12% Alternatively, if you have 200 in A1 and 0,12 in B1, type =A1*B1. Either option will give you 24 as a result. If you change the 200 or modify the percentage, the value will update automatically without you having to recalculate.

Another typical example: calculating what percentage the 40% of 340You could write directly in a cell: =340*40/100, or write 340 in one cell, 40 in another, and in a third cell put =(total_cell*percentage_cell)/100. The result in both cases is 136.

In practice, it's very convenient to write the percentage with the % symbol (for example, 40%) in a cell formatted as a percentage and then simply do total * percentage_cellThat way you don't have to keep dividing by 100 over and over again.

Display percentages and adjust decimals

When you convert a part/total formula to a percentage, Excel usually Remove default decimal placesIn other words, if the exact calculation is 0,548, applying % formatting could show you 55% by rounding.

If you need more precision, you can go to "Format Cells," choose the "Percentage" category, and increase the number of decimal places. This way, instead of 55%, you'll see, for example, 54,8% or 54,84% depending on how detailed you want the result.

This customization is important when working with financial data, notes, statistics, or any other context where One decimal place up or down can be relevantA 0,5% difference may seem insignificant in a student list, but it adds up to a considerable amount of money in a larger budget.

Percentages of multiple rows and percentages of the total

In many cases you don't just want to calculate the percentage of a single value, but see what percentage of the total does each row represent? in a data table. Excel also solves this without much complication by combining SUM and division.

Imagine a table from a small shop where column B lists the units purchased of each product. First, in a cell at the end of the column (for example, B11), you calculate the total using the formula =SUM(B2:B10). That number will be your total Shopping.

Then, in another column (for example, column C), in row 2, write the formula to find out what percentage of the total corresponds to that line: =B2/$B$11Using absolute references (with dollar signs) prevents the cell containing the total from changing when the formula is copied down.

By applying percentage formatting to column C, you will obtain the percentage for each product. percentage of total purchaseThis way you can see, for example, that a certain item represents 30% of the total, another 5%, etc.

If the same product appears in several rows and you want to know what percentage of the total the sum of all of them represents, you can use the function ADD IFFor example, if column A contains the product names and column B contains the units, and in cell E1 you write the name "Pants", in cell E2 you could put the formula =SUMIF(A2:A10,E1,B2:B10)/$B$11, which will return the percentage that all the "Pants" represent with respect to the total.

Calculate percentage changes and variations

Another very common situation is that of Compare two figures and see what percentage they have changed.For example, sales from one month to the next, website visits this year compared to last year, or kilos of a product in stock in two different inventories.

The general formula for percentage change is: (new_value − old_value) / old_valueIf you format that result as a percentage, you will see the increase or decrease expressed with the % symbol.

For example, imagine your income in November was €2342 and in December €2500. In a cell, you could write =(2500−2342)/2342. The decimal result is approximately 0,06746, which, formatted as a percentage, will be displayed as a del% increase 6,75 (depending on the number of decimal places you choose).

If your income in January is €2425 and you want to see the change compared to December, you would simply use the formula =(2425−2500)/2500. The result is −0,03 in decimal; when you apply percentage format you will see −3,00%, indicating a 3% reduction.

In monthly sales tables, it's very common to put the amounts in one column and the month-by-month growth in the adjacent column. For example, if January sales are in B2, February sales in B3, and so on, in C3 you could write =(B3−B2)/B2 and copy the formula down to monitor the evolution percentage by percentage.

Increase or decrease a value by a percentage

Excel can also help you decide How much to raise or lower an amount using a percentageThis is very useful when you adjust budgets, prices, salaries, expenses, or any other magnitude you want to modify.

The logic is simple: if you want to increase a number by X%, you multiply by (1 + X) and (1 − X)If you want to reduce it by X%, you multiply by (1 − X). In both cases, X is expressed as a decimal (for example, 0,25 for 25%).

Imagine you spend €113 a week on food and want to know how much you could spend if you increased that budget by 25%. In a free cell, you could write =113*(1+0,25). The result is 141,25 €which is your new weekly spending limit. If you work with budgets, consult personal budgets.

If instead of increasing it you want to cut that budget by 25%, the formula would be =113*(1−0,25). The result is 84,75 €which would be the new amount you should try not to exceed.

The same can be done on a monthly basis with other expenses. For example, if a company has average monthly costs of €1000 and decides to increase them by 10% to expand certain items, it would enter =1000*(1+0,10) in a cell; if it wants to decrease those expenses by 10%, it would use =1000*(1−0,10), obtaining the resulting value directly.

Calculate discounts and final prices using percentages

Percentages are essential when it comes to Calculate discounts in ExcelWhether you're buying something on sale or creating a price list for your business, it's important to know how to set up the formulas correctly.

If a product costs €50 and has a 30% discount, you want to know the final price you'll pay. A very clear way to see this is: final_price = price − (price × discount)In Excel, if the price is in A2 and the discount percentage is in B2 (such as 30% or 0,3), in C2 you could write =A2−(A2*B2).

Another equivalent, and sometimes faster, way is to multiply directly by (1 − discount_percentage). Following the example of the €50 jacket with a 30% discount, it would be enough to: =50*(1−0,30)The result will be €35, the amount you will have to pay.

This scheme also works for cases where the discounted price is the one you know and you want to find out. the original priceFor example, if a shirt is sold for €15 and you know that price is 25% less than the original, you are paying 75% of the price. In Excel, you would enter =15/0,75, and you would get €20 as the price without the discount.

When working with cells, it's very useful to have the original price in one column, the discount in another, the final price in another, and, if you want, the discounted amount in a fourth column. With simple formulas like A2*B2 and A2−(A2*B2) you can have all the information in view.

VAT, personal income tax and other taxes with percentages

In billing and accounting, whether at home or professionally, it is common to have to add or subtract taxes expressed as a percentage, such as VAT or income tax. Excel greatly speeds up this task, especially when you have several product or service lines.

To add VAT to a base price, you can follow a similar logic to that used for budget increases. If the pre-tax price is in A2 and the VAT rate (for example, 21%) is in B2, in C2 you can calculate the VAT amount using... = A2 * B2, and in D2 the total with taxes with =A2+C2.

Another more compact option is to calculate the total directly using the formula = A2 * (1 + B2)which adds 21% to 100% of the price. Thus, if the taxable base were €100, applying =100*(1+0,21) would give you €121.

In the case of personal income tax or any other concept that needs to be subtract from the totalThe logic is symmetrical but involves subtraction. If you have an amount subject to a 15% withholding tax, you can obtain the net value by typing =amount*(1−0,15). This will directly give you the amount after the withholding tax.

If you create an invoice table with columns for base, VAT, income tax, and total, you can use formulas like (base + VAT − personal income tax) in the total column to clearly show all addition and subtraction operations with percentages.