What is the percentage difference formula?

Percentage Difference = |V1 − V2| ÷ ((V1 + V2) / 2) × 100. It uses the average of both values as the reference, so the result is the same regardless of which value is V1 or V2. Example: comparing 80 and 100 → |80−100| ÷ ((80+100)/2) × 100 = 20 ÷ 90 × 100 = 22.2%.

When should I use percentage difference vs percentage change?

Use percentage difference when comparing two values of equal standing — e.g., comparing the price of two products, or two cities' populations. Use percentage change when there is a clear before/after or reference value — e.g., a price that went up, a test score that improved, year-over-year sales. Percentage change has direction (positive/negative); percentage difference is always positive.

What is the percentage difference between 60 and 80?

|60−80| ÷ ((60+80)/2) × 100 = 20 ÷ 70 × 100 = 28.57%. Note: the percentage change from 60 to 80 is ((80−60)÷60)×100 = 33.3%, and from 80 to 60 is −25%. The percentage difference (28.57%) is the symmetric version, neither value treated as reference.

Percentage Difference Calculator

Enter two values to find how far apart they are as a percentage.

Percentage Difference — Formula & Guide

Formula

% Difference = |V1 − V2| / ((V1 + V2) / 2) × 100
This is symmetric — neither value is treated as the reference.

Example: 40 vs 50

|40 − 50| / ((40 + 50) / 2) × 100 = 10 / 45 × 100 ≈ 22.22%

Frequently Asked Questions

What is the percentage difference between 50 and 75?

|50−75| ÷ ((50+75)/2) × 100 = 25 ÷ 62.5 × 100 = 40%.

Is percentage difference the same as percentage change?

No. Percentage change uses one specific value as the reference (old value). Percentage difference uses the average of both as the reference, making it symmetrical — the answer is the same whichever value you put first.

% Difference vs % Change

% Difference has no direction — answers "how far apart?"
% Change is directional — compares new to old.

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