Reverse Percentage Calculator

Mode A: original = result / (percentage / 100). Mode B: original = final / (1 + rate / 100). Mode C: original = final / (1 − rate / 100). A 20% increase from 100 is 120, so reversing 120 at 20% increase returns 100. A 20% decrease from 100 is 80, so reversing 80 at 20% decrease returns 100. Subtracting 20% of 120 does not undo a 20% increase.

Mode A — If the result is X% of the original, what was the original? B — What was the original before a percentage increase? C — What was the original before a percentage decrease? Display decimal places 0123456

Related: forward increase and decrease · reverse percentages article