Percentage Change Calculator

Percentage Change

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Absolute Change

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Direction

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What is a Percentage Change Calculator?

A percentage change calculator tells you how much a value has increased or decreased relative to where it started, expressed as a percentage. It is useful any time you are comparing a before and after value: prices, weights, scores, revenue, or anything else that changes over time.

How It Works

Subtract the original from the new value, divide by the absolute value of the original, then multiply by 100:

% change = ((New - Original) / |Original|) x 100

A positive result is an increase. A negative result is a decrease.

Example

A stock was at $45.00 last month and is now at $58.50.

  • (58.50 - 45.00) / 45.00 x 100 = +30% increase

Tips

  • Always enter the original (older) value first and the new (current) value second. Swapping them gives the wrong sign and magnitude.
  • A 100% increase means the value doubled. A 50% decrease means the value halved.
  • If the original value is zero, percentage change is undefined. You cannot divide by zero.

Frequently Asked Questions

What is the difference between percentage change and percentage difference?

Percentage change has a direction: it compares a new value to a specific starting point. Percentage difference is symmetric and has no direction: it compares two values without a defined original, dividing by their average instead.

Can percentage change exceed 100%?

Yes. If a value goes from 10 to 25, that is a 150% increase. A 100% increase means the value doubled; anything above that means it more than doubled.

What does a negative percentage change mean?

A negative result means the value decreased. A -25% change means the new value is 25% lower than the original. The maximum decrease is -100%, which would mean the value dropped to zero.

How is percentage change used in finance?

In finance, percentage change measures investment returns, price movements, revenue growth, and inflation. It lets you compare changes across different scales, so a $5 move on a $10 stock (50%) is directly comparable to a $500 move on a $1,000 bond (50%).