To help us understand percentage increase and decrease, think about the last time you watched your phone's last 1% of battery drain away…

This calculation actually uses the following percentage change formula:

Try it out yourself!

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### So there are two different percentage change equations? 🤯

Ehh, sort of. The percentage change formula above comes from a formula we may be more familiar with:

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## Percentage Increase and Percentage Decrease Calculator

## How to Find the Initial and Final Value of a Percentage Increase or Decrease

### Step 1. Convert the percentage change to a decimal.

### Step 2. Determine whether to add or subtract the change to/from 1.

- If we’re decreasing, we
**subtract**. - If we’re increasing, we
**add**.

### Step 3. Set up the equation.

or

### Step 4. Solve for the unknown.

## Calculating Final Value of Percentage Increase and Decrease

Calculating the final value of a percentage change means we want to find the amount after a percentage increase or decrease.

Let’s take a look at a few examples to make this make sense!

## Practice: Calculating Final Value of Percentage Increase and Decrease

### Step 1. Convert the percentage change to a decimal.

## Calculating Initial Value of Percentage Increase and Decrease

Calculating the initial value of a percentage change means we want to find the amount before a percentage increase or decrease.

Let’s take a look at a few examples to make this make sense!