# How to Calculate Percentage Decrease: A Step-by-Step Guide

Need to determine the percentage decrease between two values? Learning how to accurately calculate percent decrease is an important math skill with many real-world applications.

Whether you’re analyzing business metrics, investment returns, or student test scores, being able to quantify a percentage decrease helps you grasp exactly how much a value has lowered. With the right formula and understanding, it’s straightforward to figure out.

In this comprehensive guide, we’ll cover

• What percentage decrease is
• Step-by-step instructions for calculating it
• Examples covering different scenarios
• How to determine increase vs. decrease
• Applications like business, finance, and more

Follow these tips to become a pro at calculating percentage decrease and applying it to make savvy decisions,

## What is Percentage Decrease?

Percentage decrease expresses how much a value has decreased relative to the starting amount as a percentage. For example, if new software sales decline from 100 units last month to 75 units this month, the percentage decrease is 25% This quantifies the downward change

Percentage decrease helps you analyze the dimension of a decrease, not just the raw numeric difference. It standardizes the decrease on a 0 to 100% scale for easy interpretation.

Without looking at percentage decrease, it’s hard to interpret if a decrease is significant or minor. Percentages make it clear.

## How to Calculate Percentage Decrease: Simple Step-by-Step

Figuring out percentage decrease is straightforward using this 3-step process:

### Step 1) Subtract New Value from Original Value

Take the original starting value and subtract the new, lowered value after the decrease.

For example, if sales declined from 100 units originally to 75 units now, you would calculate:
100 (original units)
-75 (new units)
= 25

This gives the raw decrease amount.

### Step 2) Divide Decrease Amount by Original Value

Next, divide the decrease amount by the absolute original starting value.

Continuing the sales example:
25 (decrease amount)
/ 100 (original value)
= 0.25

This converts the decrease to a decimal form.

### Step 3) Convert to Percentage

Multiply the decimal number by 100 to express it as a percentage:
0.25 x 100 = 25% decrease

That’s it! Following these 3 simple steps allows you to calculate the percentage decrease for any two values.

## Calculating Percentage Decrease Example

Let’s walk through a detailed example:

A retailer wants to determine the percentage decrease in sales from January to February.

• In January, sales were \$50,000
• In February, sales were \$40,000

Step 1) Subtract starting value minus new value after decrease:
\$50,000 (starting sales)

• \$40,000 (new sales)
= \$10,000 decrease

Step 2) Divide decrease amount by original starting value:
\$10,000 decrease
/ \$50,000 original value
= 0.2

Step 3) Convert to percentage:
0.2 x 100 = 20% decrease

Therefore, the percentage decrease in monthly sales was 20%.

This quantifies the change in sales as a percentage relative to the original amount.

## Calculating Percentage Decrease Without Negative Sign

When subtracting a smaller number from a larger one, the decrease amount results in a negative number, like -25 in the earlier example.

You can calculate the percentage without the negative sign by taking the absolute value of the decrease amount before dividing:

|25| (absolute decrease value)
/ 100 (original value)
= 0.25

0.25 x 100 = 25% decrease

Either method works fine. Just be consistent within a calculation.

## Determining Percentage Increase vs. Decrease

How can you tell at a glance whether a percentage change is an increase or decrease?

• If the percentage is positive, it is a percentage increase

• If the percentage is negative, it is a percentage decrease

The sign of the percentage tells you whether the change is up or down relative to the starting value.

## Applications of Percentage Decrease

Calculating percentage decrease is useful in many real-world applications:

Compare monthly or annual sales/revenue figures to quantify decrease percentages. This helps analyze performance.

### Investment Returns

Calculate the percentage decrease in the value of an investment portfolio over time.

### Real Estate Prices

Determine the percentage decrease in housing prices during downturn markets.

### Student Test Scores

Analyze percentage decreases in student test scores to identify gaps.

### Manufacturing Defects

Quantify the percentage decrease in product defects after implementing a quality program.

Anywhere you need to evaluate by how much a metric or value has lowered, calculating percentage decrease provides key insights!

## Tips for Accurately Calculating Percentage Decrease

Follow these tips for accurate percentage decrease calculations:

• Use raw data rather than estimates whenever possible.
• Take absolute values before dividing to avoid negative signs.
• Double check your math – use a calculator to be sure.
• Analyze multiple time periods to identify trends.
• Compare percentages against targets to gauge performance.
• Make sure your original starting value is higher than the new value.
• Watch for very small original values that skew percentages.

With practice, calculating percentage decrease becomes second nature!

## Key Takeaways on Percentage Decrease

The key concepts to remember:

• Percentage decrease quantifies a lowered value relative to the original starting amount.

• Follow three simple steps: subtract new from old, divide decrease by original, convert to percentage.

• A positive percentage is an increase, while a negative percentage is a decrease.

• Percentage decrease provides useful insight across business, finance, education and more.

• Take care to calculate accurately and interpret percentages appropriately.

Learning this fundamental math skill empowers you to analyze decreases and make informed decisions confidently. Master the art of calculating percentage decrease!

## Find the percentage of change between two numbers

In this example, your earnings are \$2,342 in November and \$2,500 in December. What is the percentage of change in your earnings between these two months? Then, if your earnings are \$2,425 in January, what is the percentage of change in your earnings between December and January? You can calculate the difference by subtracting your new earnings from your original earnings, and then dividing the result by your original earnings.

Calculate a percentage of increase

• Select any blank cell.
• Type =(2500-2342)/2342, and then press RETURN . The result is 0.06746.
• Select the cell that contains the result from step 2.
• On the Home tab, select . The result is 6.75%, which is the percentage of increase in earnings. Note: To change the number of decimal places that appear in the result, select Increase Decimal or Decrease Decimal .

Calculate a percentage of decrease

• Select any blank cell.
• Type =(2425-2500)/2500, and then press RETURN . The result is -0.03000.
• Select the cell that contains the result from step 2.
• On the Home tab, select . The result is -3.00%, which is the percentage of decrease in earnings. Note: To change the number of decimal places that appear in the result, select Increase Decimal or Decrease Decimal .

## Find the percentage of a total

Lets say that you answered 42 questions out of 50 correctly on a test. What is the percentage of correct answers?

• Select any blank cell.
• Type =42/50, and then press RETURN . The result is 0.84.
• Select the cell that contains the result from step 2.
• On the Home tab, select . The result is 84.00%, which is the percentage of correct answers on the test. Note: To change the number of decimal places that appear in the result, select Increase Decimal or Decrease Decimal .