Percentage Change Calculator
Calculate the exact percent increase or decrease between any two values.
About Percentage Change Calculator
Percentage change measures how much a value moved relative to where it started, and it shows up in almost every field that tracks numbers over time. Stock moves, price rises, sales growth, and population shifts are all commonly reported as percentage change so that changes of very different sizes can be compared on the same scale.
The math is (new − old) ÷ old × 100. A positive result is an increase and a negative result is a decrease, and the tool labels the direction for you. Two caveats matter. Starting from zero is undefined because you cannot divide by zero. And the base matters: a rise from 10 to 11 is a 10% increase, while reversing from 11 to 10 is only a 9.1% decrease.
Investors use it to judge returns, retailers track month-over-month sales, and analysts compare growth across companies of different sizes. It is also the natural tool for anyone reviewing price rises, salary changes, or progress metrics recorded over weeks and months, since a single number summarizes the whole move.
How to Use
- Enter the original (old) value.
- Enter the new value.
- Read the percentage change, labeled increase or decrease.
Example
Old: 80, New: 100 +25.0% (increase of 20)
(100 - 80) ÷ 80 × 100 = 25%. The result is positive, so it's a 25% increase.
FAQ
What if the new value is lower?
The result is negative, reported as a percentage decrease, so you always know the direction.
Is percentage change the same as percentage difference?
Not exactly. Change is relative to the starting value; difference uses the average of the two as the base.
Can it handle going from zero?
Division by zero isn't defined, so the tool shows a clear message instead of an error.
What is the difference between percentage change and percentage points?
A rise from 4% to 5% is a 25% increase but only a 1 percentage-point change. Percentage points describe the raw difference; percentage change describes it relative to the starting rate.
How do I calculate percentage change over multiple periods?
Apply the change to each period in sequence rather than adding the percentages. A 50% rise followed by a 50% fall leaves you at 75% of the original, not back where you started.