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Reverse Percentage Formula:
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Reverse percentage calculation is used to find the original value before a percentage increase or decrease was applied. It's commonly needed when you know the final value after a percentage change and want to determine the starting value.
The calculator uses the reverse percentage formula:
Where:
Explanation: The formula reverses the standard percentage calculation by dividing the final value by (1 + percentage/100).
Details: Reverse percentage calculations are used in finance (calculating pre-tax prices), retail (determining original prices before discounts), and data analysis (recovering original values from percentage-transformed data).
Tips: Enter the final value and the percentage change (use positive for increase, negative for decrease). For example, to find the original price before a 20% discount that resulted in $80, enter 80 as final value and -20 as percentage.
Q1: What's the difference between percentage and reverse percentage?
A: Standard percentage calculates a new value from an original, while reverse percentage calculates the original from the new value.
Q2: Can this be used for compound percentage changes?
A: No, this calculator handles single percentage changes. Compound changes require a different formula.
Q3: How do I calculate a price before tax?
A: If the tax rate is 10% and total is $110, enter 110 as final value and 10 as percentage.
Q4: What if I know the percentage of the original, not the change?
A: This calculator requires the percentage change. If you know the final is 80% of original, that's a 20% decrease.
Q5: Why is my result not matching manual calculations?
A: Check if you're using the correct sign for the percentage (positive for increase, negative for decrease).