Percentage Difference Calculator
The percentage difference between two numbers, with the formula printed beside the answer rather than hidden behind it. This page opens on 80 and 100, which are 22.222222% apart: the difference divides by the average of the two, so swapping them changes nothing. That is what makes it a different figure from percentage change, which divides by where you started and calls the same pair a 25% increase.
What is the percentage difference between 80 and 100?Symmetric: swapping the two values gives the same answer, unlike percentage change.
Change and difference are not the same thing. Going from 80 to 100 is a 25% increase, measured against where you started. But the percentage difference between 80 and 100 is 22.22%, because that one divides by the average of the two. Change has a direction; difference does not. Reports and spreadsheets mix these up constantly, which is why both are here as separate questions.
Margin and markup are the same profit over two different divisors. Something that costs 40 and sells for 100 earns 60 either way, but the margin divides that by the selling price and is 60%, while the markup divides it by the cost and is 150%. Margin can never pass 100%; markup has no ceiling. The profit margin question above reports both, each beside the number it divided by.
Common questions
- What is the percentage difference formula?
- The gap between the two values, divided by the average of their sizes, times 100. The tool prints it for the numbers you enter: for 80 and 100 it shows |80 − 100| ÷ ((|80| + |100|) ÷ 2) × 100, which is 20 ÷ 90 × 100, or 22.222222%. Magnitudes are used on the bottom so a pair with a negative in it still divides by a positive average.
- What is the percentage difference between 80 and 100?
- 22.222222%, and 22.22% once it is rounded for a report. That is the figure this page opens on. Enter the pair the other way round and it does not move, because the divisor is the average of the two rather than one of them.
- How is percentage difference different from percentage change?
- Change has a direction and divides by the starting value; difference has none and divides by the average. Going from 80 to 100 is a 25% increase and going back from 100 to 80 is a 20% decrease, but the difference between 80 and 100 is 22.222222% whichever way you read it. Use change when one value came before the other, and difference when neither did, as with two measurements of the same thing.
- Can the percentage difference be more than 100%?
- Yes. Two values as far apart as 10 and 200 give 180.952381%, because the gap of 190 is nearly twice their average of 105. The ceiling is 200%, which is what you get when one value is zero and the other is not, and the tool refuses only the pair where both are zero: there is no difference between nothing and nothing to express as a proportion.
- Which mode should I use for a discount or a growth rate?
- Neither of these. A discount is the % off a price question, and a growth rate is % increase or decrease, since a starting figure exists and the direction matters. Percentage difference is for comparing two figures that stand side by side, like two labs measuring the same sample.
Exact, computed in double precision and cleaned to twelve significant digits, with the working shown.