Percentage Change Calculator
Enter the old and new values to measure an increase or decrease relative to the old value.
Verify this calculatorMaintained
See what the result uses—and what it cannot know.
Sumvoro calculates deterministically from the visible inputs. It does not invent lender terms, local rules, market values, medical facts, or professional judgments.
- 1 · InputsCheck every entered value against the latest statement, quote, measurement, or official source.
- 2 · Formula
Percentage change = (new value − old value) ÷ old value × 100. An old value of zero has no defined percentage-change result. - 3 · SensitivityUse Insights to run a lower and higher case. If the conclusion changes easily, collect better information or leave more margin.
- 4 · ScopeThis tool is maintained and covered by automated calculation tests. Provider timing, rounding, and omitted facts can still change a real-world result.
- Formula release
- 2026.10-r4
- Release date
- October 10, 2026
- Review status
- Maintained
- Source review
- September 12, 2026
Optional readingLearn how this calculator works
How the percentage change calculator works
Enter the old and new values to measure an increase or decrease relative to the old value.
Percentage change = (new value − old value) ÷ old value × 100. An old value of zero has no defined percentage-change result.
Read our calculation methodology and limitations.
Example
Going from 80 to 100 is a 25% increase. Going back from 100 to 80 is a 20% decrease because the comparison starts from a different base.
What affects the result
- The old value is the denominator, so reversing the values changes the percentage.
- A negative result means a decrease.
- A zero starting value cannot provide a percentage base.
Frequently asked questions
Why are the increase and decrease different?
Each uses its own starting value as the base. A change of 20 is 25% of 80 but 20% of 100.
Is a rate moving from 5% to 6% a 1% increase?
It rises by one percentage point, or 20% relative to the original 5% rate. These are different measures.