Percentage Difference Calculator

Not percent change from an old value, and not a sale markdown. Click any i for detail.

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Two values

A
i
A

First number. Order does not matter.

B
i
B

Second number.

How to use this calculator

  1. Enter any two numbers.
  2. Read the symmetric % difference.
  3. Percent change from old → new is percentage increase.
  4. A shelf markdown is percent-off.

Results explained

|A − B| / ((|A| + |B|) / 2) × 100. Swapping A and B leaves the result unchanged.

Quick reference: three percents

80 vs 100 is 22.22% difference, 25% increase from 80, or 20% off 100.

ItemDetail
This pageSymmetric difference
Percentage increase(new−old)/|old|
Percent offSale markdown
z-scoreSDs from a mean

If both values are 0, the difference is undefined in this model (we show 0).

How the estimate is built

% diff = |A−B| / ((|A|+|B|)/2) × 100.

Example scenario

80 and 100 → |20| / 90 → 22.22%.

FAQ

Which is the baseline?

Neither — that’s why it is symmetric.

Negative numbers?

We use absolute values in the mean so the scale stays positive.

Statistics class mean?

Mean/median/mode is the list-stats page.