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Percentage difference calculator

Compute the percentage difference between two values (relative to their average).

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Need Percentage difference? The Percentage difference calculator derives it from Value A, Value B in one step. For instance, with Value A = 40 and Value B = 60 it returns Percentage difference = 40%.

How to use it

  1. Enter your values: Value A, Value B.
  2. Read the result instantly: Percentage difference.

Frequently asked questions

What does the Percentage difference calculator actually compute?

It takes Value A and Value B and derives Percentage difference from them. The calculation is live as you type, so the result updates on every change.

What information do I need to provide?

2 values: Value A and Value B. Nothing else is required — no account, no file upload.

Can you show a worked example?

With Value A = 40 and Value B = 60, the calculator returns Percentage difference = 40%. Those figures come from running this exact tool, so you can reproduce them by entering the same values.

When would I actually use this?

The everyday cases: a discount at the till, a rise or fall between two figures, the price before tax, and working backwards from a total.

What is the most common mistake?

Undoing a percentage by applying it again. Take 20% off 100 and you get 80; add 20% to 80 and you get 96, not 100 — the two operations use different bases.

What is the difference between the Percentage difference calculator and the Percentage change calculator?

This one returns Percentage difference; the Percentage change calculator returns Change and Difference. That is the whole difference — open the one whose figure you need.

Is there a tool for the next step?

Percentage error calculator is the closest one after this: Compute the percentage error between a measured and a true value.

What else is worth having open alongside it?

Percentage decrease calculator and Percentage increase calculator — they come up in the same task often enough to be worth a second tab.

Where do the figures come from, and how current are they?

Percentage arithmetic is exact and universal. Where a result is a rate rather than an amount, the tool states the base it was taken on, because that is where the ambiguity lives.

Further reading

All guides →
ExplainerPercentage Difference vs. Percentage Change vs. Percentage ErrorThree percentages that look alike but answer different questions. Learn the formula for each, when to use it, and why they give different numbers.How-toHow to Calculate Percent Error: The Accuracy Formula for SciencePercent error tells you how close a measurement is to the true value. Learn the formula, work through an example, and see how scientists use it to judge accuracy.How-toHow to Calculate a Weighted AverageA weighted average gives some values more influence than others. Learn the Σ(w·x) / Σw formula with grade and portfolio examples you can follow step by step.How-toHow to Find the Area of a Triangle: Base × Height and Heron's FormulaTwo reliable ways to find a triangle's area: half base times height when you know the height, and Heron's formula when you only know the three sides.ExplainerWhat Is Aspect Ratio? 16:9, 4:3 and How to Compute ItAspect ratio is the proportion of width to height. Learn what 16:9 and 4:3 mean, how to compute a ratio from pixel dimensions, and where each ratio is used.How-toHow to Convert a Percentage to a Fraction: Over 100, Then ReduceA percentage is just a fraction out of 100. Put the number over 100, reduce to lowest terms, and handle decimal percentages like 12.5% by clearing the decimal first. With examples.