Percentage Change Calculator

Find the percentage increase or decrease between two values.

Worked example

Going from 50 to 75 is a 50% increase, because (75 − 50) ÷ 50 × 100 = 50.

How it works

This tool calculates how much a value has changed, as a percentage of the original value, using (new − original) ÷ original × 100. An original value of zero has no defined percentage change, since it would require dividing by zero. When the original value is negative, this tool shows the signed percentage-change figure but does not label it a plain "increase" or "decrease". With a negative starting value, that formula's sign can point the opposite way from what the numbers intuitively suggest, so labelling it either way risks misleading you.

What this result means

The result is the percentage the value has increased or decreased by, relative to the original value.

Common mistakes

With a negative starting value, "increase" and "decrease" can be misleading — the calculator reports the signed change directly for these cases rather than guessing a label that might read the wrong way round.

Assumptions and limitations

An original value of zero has no defined percentage change and is rejected rather than shown as infinite.