Reverse Percentage Calculator: Find the Original Number

The Reverse Percentage Calculator finds the original number based on the final number and the percentage change.

Reverse Percentage Calculator After a % increase/decrease, the number is .
What was the original number?
TypeOriginal Number

How to Use Reverse Percentage Calculator

  1. Enter Percentage: Input the percentage that was either increased or decreased into the first input field.
  2. Enter Final Amount: Input the final value you have after the percentage change into the second input field.

The calculator will automatically compute and display the original amount for both increase and decrease scenarios in the table below.


Scenario: You have $78, which is 15% more than the original amount.

  • Step 1: Enter 15 in the “Percentage” field.
  • Step 2: Enter 78 in the “Final Amount” field.
  • Step 3: Check the “Increase” row in the table to find the original amount.


  • If the input is invalid (e.g., non-numeric values), the results will show ‘?’.
  • This tool is useful for finance, sales, and any situation requiring reverse percentage calculations.