Percentage Change Calculator
Find the percentage increase or decrease between two values.
Result
Enter any two values and Numerila will work out the third.
Formula:
Using your values:
Worked example
Going from 50 to 75 is a 50% increase, because (75 − 50) ÷ 50 × 100 = 50. Entering 50 and 50% instead gives 75, and entering 75 and 50% gives 50.
How it works
The three boxes are linked by one relationship: New value = Original value × (1 + Change ÷ 100). With an original and a new value it finds the change, as a percentage of the original: (new − original) ÷ original × 100. With an original value and a change it finds the new value. With a new value and a change it finds the original value. An original value of zero has no defined percentage change, since it would require dividing by zero, and a 100% decrease always leaves zero, so it cannot be traced back to an original. When the original value is negative, this tool shows the signed percentage-change figure but does not label it a plain "increase" or "decrease". With a negative starting value, that formula's sign can point the opposite way from what the numbers intuitively suggest, so labelling it either way risks misleading you.
A result written as a plain number is exact. A result starting with “≈” has been rounded to 10 significant figures, because its exact decimal never ends or is too long to read comfortably. When an exact value is long, its full digits are shown underneath. The calculation itself is never rounded: only the display is.
What this result means
The box marked Calculated holds whichever of the original value, the new value or the percentage change the other two determine. A percentage change is how much a value has increased or decreased by, relative to the original value.
Common mistakes
- With a negative starting value, "increase" and "decrease" can be misleading, so the calculator reports the signed change directly for these cases rather than guessing a label that might read the wrong way round.
Assumptions and limitations
- An original value of zero has no defined percentage change and is rejected rather than shown as infinite. A 100% decrease always leaves zero, so the original cannot be found from a result of zero.