What this tool is for
Percentage Change Calculator handles a focused everyday calculation job: find the percentage increase or decrease from an old value to a new value. It is intentionally narrow so the formula and example stay visible beside the tool.
When to use it
Use it when you want to verify percentage change quickly, compare a few values, or explain the calculation to someone else without opening a spreadsheet.
Input notes
- Enter values that match the units or dates requested by the form.
- Use the reset state as a quick reference when you want to see a normal percentage change example.
- Review the limitation note before using the result outside a quick estimate.
Formula
percentage change = ((new value - old value) / |old value|) x 100
Worked example
Going from 80 to 100 is ((100 - 80) / 80) x 100 = 25%.
What the result means
The output follows percentage change = ((new value - old value) / |old value|) x 100. The worked example shows the same calculation with real values: Going from 80 to 100 is ((100 - 80) / 80) x 100 = 25%.
Limitations
The original value cannot be zero. This tool describes arithmetic change, not financial performance.
Before you rely on the result
Use the number as a quick arithmetic result. For legal, payroll, tax, or financial decisions, compare it with an authoritative source.
Privacy note
This page uses browser JavaScript only for the calculation. Marketivate does not need an account, upload, or database entry to produce the result.
Frequently asked questions
Why use the absolute old value?
It keeps the sign focused on direction while measuring change against the original magnitude.
Is a negative result a decrease?
Yes. A negative percentage means the new value is lower than the original value.
Last reviewed: 2026-07-11