How to Easily Increase a Number by a Percentage in Excel

Increasing a number by a percentage is a common task in Excel. Whether you’re calculating price increases, raises, interest rates, or any other growth metric, being able to increase a number by a percentage quickly and easily is an important Excel skill.

In this step-by-step guide, I’ll show you two simple methods to increase a number by a percentage in Excel using basic formulas. We’ll cover how to:

• Increase a number by a percentage using the PRODUCT and SUM formulas
• Increase a number by a percentage using only the PRODUCT formula
• Format the results as currency or with a percentage symbol

These methods work for any percentage increase or decrease I’ll use simple examples with sample numbers so you can clearly see how the formulas work

Overview of Increasing a Number by a Percentage

Increasing a number by a percentage involves multiplying the original number by 1 plus the percentage

For example, to increase 113 by 25%, you would calculate:

113 * (1 + 25%)

Which is:

113 * (1 + 0.25) = 113 * 1.25 = 141.25

So 113 increased by 25% is 141.25.

The key is understanding that to increase a number by 25%, you take the original number and multiply it by 1.25 (which is 1 + 0.25, or 125%).

This same concept applies to any percentage increase or decrease. The formula is:

Original Number * (1 + Percentage in Decimal Form)

Below I’ll show you how to calculate this in Excel using simple formulas.

Method 1: Increase a Number by a Percentage Using SUM and PRODUCT

The first method to increase a number by a percentage uses both the SUM and PRODUCT functions.

Here are the steps:

1. Enter the original number in any cell (A1 in this example).

2. In another cell (B1), enter the percentage increase or decrease as a decimal. For a 25% increase enter 0.25. For a 10% decrease enter -0.1.

3. In another cell (C1), enter the formula =SUM(1,B1). This adds 1 plus the percentage.

4. Finally, in another cell (D1), use the PRODUCT formula to multiply the original number by the sum calculated above: =PRODUCT(A1,C1)

This multiplies the original number by 1 plus the percentage to increase or decrease it.

For example:

A1: 113B1: 0.25  C1: =SUM(1,B1)         = 1.25D1: =PRODUCT(A1,C1)       = 141.25

So for an original number of 113 and a 25% increase, the final result is 141.25.

This method works for both percentage increases and decreases. Just change the percentage in step 2 to a negative number for a decrease.

The benefit of this method is it breaks the calculation down into small steps that are easy to understand. The downside is it uses two formulas instead of just one.

Next, I’ll show you an even easier method.

Method 2: Increase a Number by a Percentage Using Only PRODUCT

An even simpler way to increase a number by a percentage in Excel is to use only the PRODUCT formula.

Here are the steps:

1. Enter the original number in any cell (A2 in this example).

2. In another cell (B2), enter the percentage increase or decrease as a decimal. For a 25% increase enter 0.25.

3. In another cell (C2), use this PRODUCT formula: =PRODUCT(A2,1+B2)

That’s it! The formula multiplies the original number by 1 plus the percentage to increase or decrease it.

For example:

A2: 113B2: 0.25C2: =PRODUCT(A2,1+B2)         = 141.25

This method combines steps 3 and 4 from the previous example into a single formula.

Formatting the Results as Currency or Percentage

Once you have the calculated results, you can format them as currency or percentages for better readability:

• To format as currency, select the cells with the results, click the Home tab, then click the Currency Number Format button. This displays the results with a currency symbol and two decimal places.

• To format as a percentage, select the cells with the results, click the Home tab, then click the Percent Style button. This displays the results followed by a percentage symbol.

So for the above examples, you could format cell D1 or C2 as currency to display $141.25 or format it as a percentage to display 141.25%.

Increasing a Number by a Percentage In Practice

Now let’s look at a few examples of how to use these methods in practice.

Example 1: Calculating Price Increase

Say your product costs $100 normally. You want to calculate the new price after increasing it by 10%.

Using Method 1:

A3: 100B3: 0.10 C3: =SUM(1,B3)     = 1.10D3: =PRODUCT(A3,C3)      = 110

So a 10% price increase on a $100 product is $110.

Using Method 2:

A4: 100B4: 0.10C4: =PRODUCT(A4,1+B4)    = 110

Example 2: Calculating Interest Earned

If you have $5,000 invested earning 4% annual interest, how much interest will you earn in a year?

Using Method 1:

A5: 5000B5: 0.04C5: =SUM(1,B5)     = 1.04D5: =PRODUCT(A5,C5)    = 5,200

So at a 4% interest rate, you will earn $200 interest on a $5,000 investment.

Using Method 2:

A6: 5000 B6: 0.04C6: =PRODUCT(A6,1+B6)    = 5,200 

Example 3: Calculating a Decrease

Your salary is currently $60,000. Due to company cutbacks, it will be decreased by 6%. What is your new decreased salary?

Using Method 1:

A7: 60000B7: -0.06C7: =SUM(1,B7)      = 0.94D7: =PRODUCT(A7,C7)    = 56,400

So a 6% decrease on a $60,000 salary is $56,400.

Using Method 2:

A8: 60000B8: -0.06 C8: =PRODUCT(A8,1+B8)      = 56,400

Recap and Additional Tips

To quickly recap how to increase a number by a percentage in Excel:

• Use the formula: Original Number * (1 + Percentage)
• Enter the percentage as a decimal, like 0.25 for 25%
• Use the SUM and PRODUCT formulas together or just the PRODUCT formula
• Format as currency or percent for better readability

Here are some additional tips:

• To decrease a number, enter the percentage as a negative decimal like -0.10 for a 10% decrease
• You can use a cell reference for the percentage like B1 instead of entering the decimal directly
• This works for any percentage increase or decrease, not just the examples shown
• Experiment with your own numbers to get comfortable with the formulas

Increasing numbers by percentages is a critical Excel skill used across many applications like finance, accounting, and sales. Master these simple techniques using SUM, PRODUCT, and formatting to increase your spreadsheet productivity.