Math calculator

Percentage Change Calculator

Compare an original value with a new value to measure the increase or decrease.

Deterministic math. No account required.

Your details

Your results

Numerical change+20
Original value80
New value100

The default comparison divides numerical change by the original value. Negative bases can reverse the percentage sign. Advanced offers an absolute base or symmetric difference. This is not percentage-point change.

Percentage increase25%
Relative to original

How the percentage change calculator works

Calculate the percentage increase or decrease between two nonnegative values, with the numerical difference shown separately.

Formula

Percentage change = (new value − original value) ÷ original value × 100.

Example

A change from 80 to 100 is a 25% increase. Going from 100 back to 80 is a 20% decrease because the starting value is different.

What affects the result

  • The original value is the denominator.
  • Percentage change from zero is undefined.
  • A decrease of 100% means the new value is zero.

Frequently asked questions

Why are the reverse percentages different?

Reversing the comparison changes the denominator. An increase from 80 to 100 uses 80 as its base, while the reverse uses 100.

Is this percentage-point change?

No. A rate moving from 10% to 15% rises by 5 percentage points and by 50% relative to its original rate.

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