How do I calculate percent change?

Subtract the original value from the new value, divide by the original value, and multiply by 100. From 150 to 180 is (180 − 150) ÷ 150 × 100 = 20%.

What is the difference between an increase and a decrease?

A positive result means the value went up; a negative result means it went down. The calculator shows the sign for you.

Why isn't a rise and a fall of the same amount the same percentage?

Because percent change is relative to the starting value. Going from 150 to 180 is +20%, but going from 180 to 150 is −16.67%, since the starting points differ.

Why can't the original value be zero?

Percent change is measured relative to the original value, and dividing by zero has no defined result. Enter a non-zero original value.

Results are shown rounded to two decimals. The calculation behind them uses full precision.

Can I share a calculation?

Yes. Use Share to copy a link that reopens the calculator with the same two values.

Percent change calculator

Enter the original value and the new value. The calculator shows the percent change and the absolute difference as you type.

Use it to find how much a number went up or down in percentage terms, from one value to the next.

Original value

New value

Percent change

+20%

Absolute change: +30

The result updates as you type. A positive number is an increase; a negative number is a decrease. The bars compare the two values.

How does it work?

A positive result is an increase, a negative result is a decrease. The change is measured against the magnitude of the original value.

Percent change formula

\frac{\text{new} - \text{old}}{\lvert \text{old} \rvert} \times 100

old: The original value you are comparing from.
new: The new value you are comparing to.

From 150 to 180 is (180 − 150) ÷ 150 × 100 = +20%.

Method & sources

Inputs are treated as plain numbers without units or currency. The change is measured against the magnitude of the original value, so the original value cannot be zero.

Sources

Where this method comes from — use these references to understand the formula, assumptions, and limits.

Percent change — National Institute of Standards and Technology, verified 2026-06-10

How we calculate

Inputs are treated as plain numbers without units or currency.
The change is measured against the magnitude of the original value, so the original value cannot be zero.

Rounding

Results are rounded to two decimals for display. The calculation itself uses full precision.

What this calculator does

Percent change tells you how much a value grew or shrank relative to where it started. This calculator takes an original value and a new value and gives you both the percentage and the plain difference between them.

How to use it

Enter the original value — where the number started.
Enter the new value — where it ended up.
Read the percent change and the absolute change below.

A worked example

A subscription rises from 150 to 180. Enter 150 as the original value and 180 as the new value, and you get +20%, an absolute change of +30. If it instead dropped from 180 to 150, you would see −16.67%.

Common mistakes

Swapping the original and new values. The original is the value you compare against.
Reading the percentage as the new total. A +20% change on 150 is an increase of 30, ending at 180.
Expecting a fall and a rise of the same size to use the same percentage. Going 150 → 180 is +20%, but 180 → 150 is −16.67%, because the starting points differ.

When it's useful

Price rises, salary changes, traffic and growth metrics, before-and-after comparisons, and any time you need to express a difference as a percentage.

FAQ

How do I calculate percent change?: Subtract the original value from the new value, divide by the original value, and multiply by 100. From 150 to 180 is (180 − 150) ÷ 150 × 100 = 20%.
What is the difference between an increase and a decrease?: A positive result means the value went up; a negative result means it went down. The calculator shows the sign for you.
Why isn't a rise and a fall of the same amount the same percentage?: Because percent change is relative to the starting value. Going from 150 to 180 is +20%, but going from 180 to 150 is −16.67%, since the starting points differ.
Why can't the original value be zero?: Percent change is measured relative to the original value, and dividing by zero has no defined result. Enter a non-zero original value.
Are results rounded?: Results are shown rounded to two decimals. The calculation behind them uses full precision.
Can I share a calculation?: Yes. Use Share to copy a link that reopens the calculator with the same two values.

Related calculators

Embed this calculator

Add this calculator to your own site. The snippet includes the calculator iframe and a small attribution link:

<iframe src="https://wisecalcs.com/embed/en/percent-change-calculator" width="100%" height="520" style="border:0" loading="lazy"></iframe>
<p>Calculator from <a href="https://wisecalcs.com/en/math/percent-change-calculator">WiseCalcs</a></p>