Reverse Percentage Calculator
Enter the current value and the percentage change that produced it.
A QUICK WALKTHROUGH
How to use this tool
- Enter a current value.
- Enter a percentage from -99.999999 to 1,000,000.
- Choose increase or decrease and calculate the original value.
Defined reverse formula
For an increase, original = current / (1 + rate). For a decrease, original = current / (1 − rate).
Safe boundaries
Decrease rates must be below 100%; zero denominators and non-finite values are rejected. Results are rounded to 10 decimal places.
GOOD TO KNOW
Common questions
Can I reverse a 100% decrease?
No. It would divide by zero.
Can percentages be negative?
Enter the direction explicitly; negative rates are rejected.