Pay Gap Calculator
What is the difference between a mean and a median pay gap?
The mean gap is moved a long way by a few very high earners; the median gap is not moved by them at all. On the figures this page opens with the mean gap is 24.89% and the median gap is 2.90% — almost twenty-two points apart, because one salary of 140,000 sits in one group. When they disagree like that, the gap is about who holds the senior roles, not about what two people doing the same job are paid.
A pay gap is not unequal pay for the same work. Running the two together is the commonest mistake in the subject.
This gives you the mean and the median side by side, and the distance between them - which is usually the most informative number on the page.
Built by Muhammad Shahzeb Anwar, MSc Industrial and Organizational Psychology, who also writes the paid version of this tool. A pay gap and unequal pay are different questions, and this page keeps them apart.
Mean and median, side by side
Paste each group's pay figures separated by commas, spaces or new lines. Any currency, as long as both lists use the same one.
A pay gap is not unequal pay
Unequal pay is two people doing the same job for different money. In most countries that has been unlawful for decades and it is a question about individual pay decisions.
A pay gap is the difference between the average pay of two groups across a whole organisation. You can have a large pay gap while paying everybody in every role identically - if one group holds most of the senior roles, the averages differ even though no individual is paid unfairly.
They are different questions with different answers, and running them together is how a reporting exercise turns into an argument nobody can win.
Why the mean and the median disagree
The mean adds everything up and divides. One director on a very large salary pulls it noticeably.
The median lines everybody up and takes the person in the middle. That same director moves it by nothing at all.
So when the mean gap is much larger than the median gap, the arithmetic is telling you the difference lives at the top of the distribution, not across it. The figures this page opens with are built to show exactly that: one high earner in group A, and a mean gap roughly twenty-two points above the median gap.
If instead the two measures are close, the gap runs through the whole payroll and the top quarter is not the explanation.
Why it refuses on small groups
With fewer than about eight people in a group, one person joining or leaving moves the percentage further than any real difference in pay. A figure that unstable is not a finding, and publishing it as one invites a conclusion the numbers cannot carry.
This tool shows the arithmetic and withholds the word. You can lower the floor if you want to, but the instability does not go away because the setting changed.
What this will not tell you
This computes two averages and the distance between them. It cannot tell you whether a gap is unfair, what caused it, or what to do about it. It is not a statutory reporting tool, it makes no claim about any reporting obligation you may have, and it is not legal advice.
Questions people actually ask
What is the difference between the mean and median pay gap?
The mean is the average of everybody's pay, so a few very high earners pull it. The median is the middle person's pay, which those same high earners do not move. When the mean gap is much larger than the median gap, the difference is concentrated at the top of the organisation rather than spread across it.
Does a pay gap mean people are paid unfairly for the same job?
No. That is unequal pay, which is a different question. An organisation can pay everybody in every role identically and still report a large pay gap, if one group holds most of the senior roles.
How many people do I need before the number means anything?
This tool will not report a gap from fewer than eight people in a group, and eight is a floor rather than a comfortable number. Below it, one person joining or leaving moves the percentage more than any real pay difference does.
Is my payroll data uploaded anywhere?
No. The calculation runs in your browser. Nothing is sent to a server, nothing is stored, and there is no sign-up.
Cite this tool
Free to use and free to quote. If a figure here is useful in something you are writing, a link back is all that is asked.
Muhammad Shahzeb Anwar, MSc Industrial and Organizational Psychology. Pay Gap Calculator: Mean vs Median. Shahzeb Speaks. https://www.shahzebspeaks.com/pay-gap-calculator-3/
The other free tools
Each one answers a single question and refuses the ones it cannot. All free, none asks for an email address.
Need the quartiles as well?
The paid Pay Gap Calculator adds the part this free version leaves out: everybody ordered by pay and cut into four equal parts, with the make-up of each quarter. That is usually where a gap actually lives, and it is the view that turns a percentage into something you can act on.
See the full tool