Is reversing a percent increase the same percent decrease?

No. +25% then −20% can return to the start because the bases differ. Always recalculate from the current value.

Common Percentage Mistakes (and How to Avoid Them)

Avoid frequent percent errors: mixing up base values, confusing percentage points with percent change, stacking discounts incorrectly, and dividing by zero.

6 min read · Free educational guide

Wrong base / swapped part and whole

“40 is what percent of 200?” uses 200 as the whole. Swapping the numbers produces a different, usually unintended answer. Write “part” and “whole” before calculating.

Adding percents of different totals

You cannot always add growth rates across periods or categories without weighting. A 10% rise in a small segment and a 10% rise in a large segment are not “20% overall.”

Percentage points vs relative percent

A move from 8% to 10% is 2 percentage points, but a 25% relative increase. Say which one you mean.

Stacked discounts

Sequential percent-off deals multiply remaining shares. They are almost never the sum of the badge percentages.

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FAQ

Is reversing a percent increase the same percent decrease?: No. +25% then −20% can return to the start because the bases differ. Always recalculate from the current value.