In this article, you'll learn how to use Excel to calculate percentage change, and also how to find the increase and decrease in percentage values.

Let's get into it.

How to Calculate Percentage Change in Excel

To calculate percentage change in Excel, you'll need to use a formula.

For example, if you have two numbers, ORIGINAL and NEW, you can calculate percentage change with the following formula:

percentage change = (NEW - ORIGINAL) / ORIGINAL

Note: If the number you get is positive, for example, 0.2, then the percentage increased. If the number is negative, like -0.2, then the percentage decreased.

Let's take a look at an example:

Question
If your earnings are $1,250 in May and $1,750 in June, what is the percentage change?

Solution

(1,750 - 1,250) / 1250 = 0.4 or 40%

Now let's take a look at how to do this in Excel with a handful of data entries to better understand how Excel functions work:
STEP 1: Data Entry.
screenshot-nimbus-capture-2021.07.17-07_47_10
STEP 2: The Formula
In this case we will let A = Actual Price and B = Budget Price, so our formula will be: A/B-1. This formula will be entered in cell D2.
screenshot-nimbus-capture-2021.07.17-07_56_07
To execute the formula all we need to do is press 'Enter'. We will get our percentange change in decimal values like below:
screenshot-nimbus-capture-2021.07.17-08_00_58
STEP 3: How to add %.
To add the % sign we can either:

  1. Right click on the values and select '%', then drag the cursor down to apply changes to othe values. Or
  2. We can highlight the whole column '% Change' and select the % sign from the Home menu, under numbers in the work sheet.
    screenshot-nimbus-capture-2021.07.17-08_07_28

And that's how to calculate percentage change in Excel.

Now let's go a step further and see how to calculate percentage increase and decrease.

How to Calculate Percentage Increase in Excel

To calculate percentage increase, you'll again need two numbers, ORIGINAL and NEW.

Then use the same formula as above — subtract the original number, ORIGINAL, from the new number, NEW, and divide the sum by ORIGINAL:

percentage increase = (NEW - ORIGINAL) / ORIGINAL

Note: If the number you get is negative, for example, -0.10, then the percentage actually decreased rather than increased.

Question

Your household bill was $100 in September, but increased to $125 in October. What is the percentage increase from September to October?

Solution

(125 - 100) / 100 = 0.25 or 25%

Now let's take a look at how to do this in Excel:

screenshot-docs.google.com-2021.07.10-21_43_39

As you can see, the percentage increase between the two months is 0.25, or 25%.

To display your calculations as percentages, click the % sign in the main menu.

How to Calculate Percentage Decrease in Excel

The method to calculate percentage decrease is very similar to calculating percentage increase.

The only difference is that you subtract the ORIGINAL number from the NEW number before dividing the sum by the ORIGINAL number:

percentage decrease = (ORIGINAL - NEW) / ORIGINAL

Note: If the number you get is negative, for example, -0.10, then the percentage actually increased rather than decreased.

Question

In the previous year, your expenses were $500,000. This year, your expenses were $400,000. What is the percentage decrease of your expenses this year compared to last year?

Solution

(500,000 - 400,000) / 500,000 = 0.2 or 20%

And here's how to calculate percentage decrease in Excel:

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Now that you know how to calculate percentage change, increase, and decrease in Excel, let's go over some common errors you might encounter.

Common Excel Errors When Using Formulas

Here's a short list of common errors you might run into while using Excel formulas:

  • #DIV/0!: Occurs if you attempt to divide a number by zero
  • #VALUE: Occurs when cells are left blank, or when a function is expecting a number but you pass it text instead
  • NUM!: Occurs when a formula contains invalid numeric values

Conclusion

Now you should know how to perform these calculations by hand, and how to use Excel to perform the same calculations.

Here's a quick recap of the formulas we covered:

  • percentage change = (NEW - ORIGINAL) / ORIGINAL
  • percentage increase = (NEW - ORIGINAL) / ORIGINAL
  • percentage decrease = (ORIGINAL - NEW) / ORIGINAL

And to get a better understanding of Excel features, here are some helpful links:

  1. Microsoft Excel Tutorial for Beginners - Full Course
  2. Percentage Change Practice Questions

Happy Coding ❤