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Percentage Change Calculator: Increase and Decrease Between Two Numbers

Enter an original value and a new value to get the exact percentage change, whether it is an increase or a decrease, and the raw difference, instantly and free.

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Percentage change
+25%
Absolute difference
+30

Built by Rankite, the SEO team behind Swordfish AI's +400% revenue and Zluri's +45% organic growth. See the case studies

Percentage change tells you how much a number has grown or shrunk relative to where it started. It is the number behind month over month traffic, price rises, conversion lifts and year on year revenue. This calculator takes your original value and your new value and returns the percentage change, whether it is an increase or a decrease, along with the plain difference so you can sanity check the result at a glance.

How to calculate percentage change

The formula is short: subtract the original value from the new value, divide by the original value, then multiply by 100. In symbols that is ((new minus old) divided by old) times 100. If your traffic went from 120 visits to 150, the difference is 30, divided by 120 gives 0.25, times 100 is a 25 percent increase. If it fell from 150 to 120, the same steps give a 20 percent decrease. Notice the base changed, which is why a rise and the matching fall are not the same percentage.

That last point trips a lot of people up. A jump from 100 to 150 is a 50 percent increase, but the drop back from 150 to 100 is only a 33 percent decrease, because the second calculation divides by the larger starting number. The calculator always divides by the original value you entered, so the direction is handled for you.

Percentage increase versus percentage decrease

A positive result means the new value is higher than the original, an increase. A negative result means it is lower, a decrease. The tool labels the direction and shows the raw difference next to the percentage so there is no ambiguity. This matters most when you are reporting results, because a 20 percent lift and a 20 percent drop describe very different weeks even though the number looks similar.

Where percentage change shows up in marketing

Almost every performance report is really a percentage change in disguise. Organic traffic up 18 percent since last quarter, cost per lead down 12 percent after a landing page fix, conversion rate up half a point from 2.0 to 2.5 percent, which is a 25 percent relative gain. Reading those changes correctly is the difference between a report that flatters you and one that tells the truth.

If you want changes that keep pointing up quarter after quarter, that is the outcome we build. Request a free SEO audit and we will show you where your biggest percentage gains are hiding and how to capture them.

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FAQ

Percentage Change Calculator: questions, answered

How do you calculate percentage change?
Subtract the original value from the new value, divide the result by the original value, then multiply by 100. For example, from 120 to 150 the difference is 30, divided by 120 is 0.25, times 100 gives a 25 percent increase. A negative result means the value went down.
What is the difference between percentage change and percentage difference?
Percentage change compares a new value to a specific starting value and has a direction, up or down. Percentage difference compares two values without treating either as the baseline, dividing by their average instead. Use percentage change when one number came before the other, like last month and this month.
Why is a 50 percent rise not cancelled by a 50 percent fall?
Because each percentage is taken from a different base. Rising 50 percent from 100 gets you to 150, but falling 50 percent from 150 lands at 75, not back at 100. To return exactly to 100 from 150 you need a 33 percent decrease, since that step divides by the larger number.
Can I calculate percentage change from zero?
No. If the original value is zero, the percentage change is undefined, because any increase from zero is mathematically infinite. The calculator flags this and still shows you the raw difference, which is the only meaningful figure in that case.
How do I turn a percentage change back into a value?
Multiply the original value by one plus the percentage as a decimal. A 25 percent increase on 120 is 120 times 1.25, which is 150. For a decrease, subtract instead: a 20 percent drop on 150 is 150 times 0.80, which is 120.

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