How it works
Use a positive original value. A positive result means an increase and a negative result means a decrease. From 100 to 125, the difference is 25 and the increase is 25%.
Change (%) = (new − original) / original × 100
Worked example
Show example inputs and result
Original value: 100 · New value: 125.
- Percentage change
- 25 %
- Difference
- 25
Questions and answers
Can the original value be zero?
No. Percentage change divides by the original value, so a zero base has no defined percentage change. This calculator also excludes negative bases to avoid ambiguous interpretations.
Why are some results rounded?
Results display up to 8 decimal places. Calculations use the unrounded values; very small values use scientific notation. JavaScript floating-point arithmetic can introduce tiny rounding differences.
Are my inputs sent to a server?
The calculator processes inputs in your browser. Its code does not send your values to a server.
Method reviewed: October 8, 2026 · Methods & accuracy