How to use Percentage Change Calculator
- Enter the starting value.
- Enter the new value.
- Read the percentage change and whether it is an increase or a decrease.
About this tool
The formula is (new - old) divided by the absolute value of old, multiplied by 100. A positive result is an increase and a negative result is a decrease. The old value cannot be zero because a change from zero has no defined percentage.
Use it for prices, traffic, revenue, weight or any metric measured at two points in time.
Frequently Asked Questions
- What if the old value is negative?
- The calculator divides by the absolute value of the old number, so the sign of the result still shows the direction of change.
- How do I reverse a percentage increase?
- Divide the new value by 1 plus the rate. A price of 120 after a 20% increase was 120 / 1.2 = 100 before.
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