# Add-Subtract Percentage from a Number

- by Puneet

Let’s say you have a value, and you want to add or subtract a percentage of it. For example, if you want to add 10 percent to 100, or you want to deduct 10 percent from it. It’s a quick and easy formula calculation in Excel that you can do.

Below are the formulas that you can use to increase and decrease a particular percentage from a numeric value.

• To Increase: =original_value*(100%+increase_percentage%)
• To Decrease: =original_value*(100%-decrease_percentage%)

In this tutorial, we will learn to write this formula:

## Formula to Add or Increase a Value by a Percentage

You can use the below steps:

1. First, in a cell, refer to the cell where you have the original value.
2. After that, enter the asterisk operator for multiplication.
3. Now, enter the opening parentheses and then enter “100%”.
4. Next, enter the addition operator and 10%, which is the value you want to increase with.
5. In the end, enter the closing parentheses and hit enter to get the result.
``=A1*(100%+10%)``

The moment you hit enter, it will return the value by increasing it to 110%.

You also use the formula in the flowing way where instead of using 100% you can use a 1 and for the increased percentage, you can decimal value.

``=A1*(1+0.1)``

## Formula to Subtract or Decrease a Value by a Percentage

You can use the below steps to write this formula:

1. First, enter = in a cell and refer to the cell with the original value.
2. After that, enter the closing parentheses and enter 100%.
3. Next, use the subtraction sign to deduct and enter the percentage value that you want to decrease.
4. In the end, enter the closing parentheses and hit enter to get the result.
``=A1*(100%-10%)``

The moment you hit enter, it will return a new value with a decrease.

And you can also use the formula in the following way where you can use the 1 instead of the 100%, and .1 to specify the 10%.

## How do these Formulas Work?

To understand these formulas, you need to split them into three parts:

1. Original Value
2. 100% or 1
3. Increase and Decrease (In Percentage or Decimal)

If you want to decrease a value by 15 percent, you just need to use 15% with the minus operator, or you can also use -0.15.

A percentage value is a number formatted as a percentage in Excel. When you enter 100% in a cell, Excel treats it as a 1 and formats it with the percentage. That’s why you can use 1 or 100% in the formula. And to specify the increase, you can use a decimal value or a percentage value.