1
Enter both values
Put the starting amount first and the new amount second. The starting amount must be greater than zero.
Math
Free tool
Percentage Change Calculator
Compare an original value with a new value to calculate a directional percentage increase, decrease, or no change.
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Calculate percentage change
Enter the starting value and the new value. Values must be non-negative, and the original value must be greater than zero.
Result
How to use this calculator
Three steps from your original value to an answer you can explain.
2
Calculate the change
Select Calculate percentage change to compare the two values.
3
Read the direction
The answer tells you whether the amount increased, decreased, or stayed the same.
Understand the result
Percentage change measures a directional change from an original value to a new value. The original value is the reference point, so reversing the two inputs usually changes the result.
Percentage increase and decrease formula(New − Original) ÷ Original × 100
A positive result is an increase. A negative signed result indicates a decrease; this calculator displays the magnitude together with its direction.
Worked examples
100 → 120 = +20% · 100 → 75 = −25% · 100 → 100 = 0%
These are three outcomes of the same formula: increase, decrease, and no change.
Why the starting value matters
A change of 20 has different significance when starting from 100 than when starting from 200 because the starting amount defines the reference scale. An original value of zero is undefined because the formula divides by the original value.
Percentage change vs percentage difference
Percentage change is directional and uses the original value as the denominator. Percentage Difference Calculator is symmetric and compares two values relative to their average.
More useful tools
View allFrequently asked questions
Can the new value be zero?
Yes. From a positive original value, that is a 100% decrease.
Are negative values supported?
No. This version intentionally focuses on non-negative quantities.
For a basic percentage question, use the Percentage Calculator.