What this calculation tells you
Percentage change measures movement relative to the original value. The result is labelled as an increase or decrease, while the difference card keeps the signed numerical change.
The base is important. A rise from 100 to 120 is 20%, but a fall from 120 back to 100 is about 16.67%, not 20%. This tool requires a positive original value to keep the everyday interpretation of increase and decrease unambiguous.
The method, explained
Change (%) = (new value − original value) ÷ original value × 100
The inputs use the units printed beside each field. Values shown in result cards are rounded for readability; the calculator keeps more precision while applying the formula.
A worked example
Original value: 1,000 · New value: 1,250.
Percentage increase: 25.00%
This example uses the inputs above. Your result changes when you change them.
Assumptions & limitations
- Original value must be positive; new value may be zero.
- This is percentage change, not percentage-point change between two percentage figures.
- Inputs should use the same units and measurement basis.
Questions about this tool
What are percentage points?
A move from 10% to 12% is 2 percentage points, or a 20% relative increase. The two descriptions are not interchangeable.
Can I start from zero?
No. A relative percentage change from zero is undefined; report the absolute difference instead.
Published by Sanu Tech Innovation LLP · Model notes updated 30 September 2026. Read our calculation standards or report a reproducible issue.