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Introduction Introduction # Percentage Increase and Decrease

INTRO

To help us understand percentage increase and decrease, think about the last time you watched your phone's last 1% of battery drain away… We know, it’s the worst. Now, imagine how great it would be if you could just increase your max battery by ? 🤩
Increasing by is like adding in of the old battery to get a much better new battery.
So now we have blocks of battery. And since a full block is worth hours, the new amount of battery time we have is hours.

This calculation actually uses the following percentage change formula:

And if, instead, we wanted to represent a percentage decrease, we would subtract the percentage change (in decimal format) from instead of adding it.

Try it out yourself!

✨ Drag ✨

### 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:

Check out our
Calculator
or explore our
Lesson
and
Practice
sections to learn more about how to calculate initial and final values with percentage increase and decrease.

CALCULATOR

## Percentage Increase and Percentage Decrease Calculator

What are you solving for?
What isby?
KEY STEPS

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

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

The percentage change as decimal represents the change relative to the initial value.
Remove the percentage sign and move the decimal places to the left.

### 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.

The final value equals the result from Step 2 multiplied by the initial value:

or

### Step 4. Solve for the unknown.

LESSON
Calculating Final Value of Percentage Increase and Decrease

## 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.

If the percentage change is , we use the following equation:
Which means that our final value will be greater than our initial value.

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

PRACTICE
Calculating Final Value of Percentage Increase and Decrease

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

Question 1 of 10: What is increased by ?

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

The percentage change as decimal represents the change relative to the initial value.
Remove the percentage sign and move the decimal places to the left.

LESSON
Calculating Initial Value of Percentage Increase and Decrease

## 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.

If the percentage change is , we use the following equation:
Which means that our initial value will be less than our final value.

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

PRACTICE
Calculating Initial Value of Percentage Increase and Decrease

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

Question 1 of 10: is what number increased by ?

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

The percentage change as decimal represents the change relative to the initial value.
Remove the percentage sign and move the decimal places to the left.

CONCLUSION
Nice work, look at you go! Thanks for checking out this lesson ☺️🙏. Where to next?       Leave Feedback