Calculate percentage change
The value increased by 8, which is an 11.11% increase from the old value.
Formula
Percentage change compares the difference between two numbers with the starting value. It is useful when the relative size of the change matters more than the raw difference alone.
When to use it
Use this calculator for grade movement, price changes, progress updates, budget changes, traffic changes, or any before-and-after comparison where the starting point matters.
Example interpretation
If a score moves from 72 to 80, the difference is 8 points. The percentage change is not 8%; it is 8 divided by the old value of 72, which equals about 11.11%. This matters because the same 8-point difference would be a larger percentage change from a smaller starting value.
Limitations
- The old value cannot be zero because percentage change divides by the starting value.
- A large percentage change from a very small starting value can look dramatic even when the absolute difference is small.
- The result is a comparison estimate and does not explain why the change happened.
FAQ
What formula does percentage change use?
Percentage change = (new value - old value) / absolute old value x 100.
Why can't the old value be zero?
Percentage change divides by the old value. Dividing by zero is not defined, so the calculator needs a non-zero starting value.
Is percentage change the same as difference?
No. Difference is the direct subtraction between values. Percentage change expresses that difference relative to the old value.
Privacy note
The calculator runs in the browser and does not require an account. Inputs such as scores, prices, or metrics are normal calculator values.