Calculator guide
Measure the dollar and percentage increase or decrease from an original value to a new value.
Formula or method
Change = new − original; percentage change = (new − original) / original × 100%.
How to use this calculator
- Enter the original value as the baseline.
- Enter the new value.
- Review the signed change, percentage, and direction.
Worked example
Moving from 100 to 125 is a change of 25 and a percentage increase of 25%; moving from 125 back to 100 is a 20% decrease because the baseline is now 125.
Understanding the result
The original value is always the denominator. Reversing the order changes the percentage even when the dollar difference is the same.
Limitations and assumptions
- A zero original value makes the percentage undefined; this calculator displays zero for that edge case.
- Rounding can make a displayed percentage differ slightly from hand calculations.
Frequently asked questions
How is percentage change different from percentage difference?
Percentage change uses a stated original baseline; percentage difference commonly uses the average of two values.
Can a decrease exceed 100%?
A nonnegative new value cannot fall by more than 100% from a positive original value.
What does a negative result mean?
It indicates the new value is below the original.
Sources
Educational information only; verify important decisions with a qualified professional.