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Percentage Difference Calculator

Put two numbers on the same scale and see both the dollar-style gap and the two common percentage readings.

Decision: How different are these two numbers, and which percentage should I quote?

This comparison runs in your browser. CompareMage does not send the numbers you enter to our servers.

Value A

Baseline for percent change

Value B

Comparison value

Comparison result

Value B is larger by 10.

Percent change from A to B is 25%. Symmetric percent difference is 22.22%. Use change when A is the starting point; use difference when the values are peers.

Absolute difference
10
Percent change A → B
25%
Symmetric percent difference
22.22%
B as a percent of A
125%

How to read the result

Percentages can look dramatic on small bases. A jump from 2 to 3 is a 50% change and a $1 gap. Read the absolute difference next to the percentage.

Calculated facts

Totals, differences, and break-even figures come only from the values on this page. They describe the math, not what you should do.

Decision factors

Fit, risk, time, quality, and personal constraints stay outside the calculator. A cheaper path can still be the wrong path for those reasons.

Methodology

Absolute difference is |B − A|. Symmetric percent difference is 100 × |B − A| / ((|A| + |B|) / 2). Percent change from A to B is 100 × (B − A) / A when A is not zero. The page reports which value is larger without calling either one better.

Assumptions

  • Both inputs use the same unit.
  • No inflation adjustment or time value of money is applied.

Examples

Two sticker prices

$40 and $50 differ by $10. Percent change from $40 to $50 is 25%. Symmetric percent difference is 22.22%.

Equal values

If both numbers are 80, the absolute and percentage gaps are zero. The tool reports a tie instead of inventing a winner.

How to use it

  1. Enter value A and value B in the same unit.
  2. Read the absolute gap, which value is larger, and the percentage figures.
  3. Use percent change when A is the baseline. Use percent difference when the two values are peers.

Limits

  • This is not a statistical significance test.
  • Negative inputs are allowed mathematically; interpret signs in the context of your data.

Questions

What is the difference between percent difference and percent change?

Percent change is directional: it asks how far B moved from A, using A as the base. Symmetric percent difference treats both values equally and uses their average magnitude as the base. Quote change when there is a before and after. Quote difference when there is no natural starting point.

Why is percent change blank when A is zero?

You cannot divide by zero. If the starting value is 0, a percentage change is undefined. The absolute difference is still shown.

Can I use this for prices or for counts?

Yes. The math is the same for dollars, people, or scores. Units cancel in a percentage, so keep both inputs in the same unit.

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