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Compare Two Lists

Local only — nothing is uploaded unless you save or share it.

Compare two lists and see what is only in one, only in the other, and in both.

  1. Paste the first list — one entry per line
  2. Paste the second list beside it
  3. Read what is only in A, only in B, and in both — and copy any of the three
What counts as the same

Only in the first list 

Only in the second list 
In both 
Saved comparisons
Keep a comparison you run again — the same two lists next month, with the same settings.
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    About this tool
    This is one of those jobs that sounds like a spreadsheet formula and turns into an afternoon. You have last month's subscribers and this month's, or the SKUs the warehouse has and the ones the website lists, or the guests who replied and the guests who came — and the question is always the same three: what is new, what is gone, and what is on both. Put plainly, you want to know what is in one list and not the other.

As a list comparison tool it does one thing: paste one list into each box and you get all three answers at once, each one copyable on its own. It works line by line, so anything one-per-line does: email addresses, order numbers, product codes, names, file paths, IDs.

To find differences between two lists properly, order has to stop mattering — and that is the point here. Two exports of the same data in different orders are the same list, and a tool that compares them line-against-line reports every entry as changed — which is what happens if you reach for a diff tool for this job. This treats each side as a set of entries rather than a sequence of lines.

By default it also ignores capitalisation, spaces at the ends of lines, and blank lines, because real lists disagree about all three and almost nobody means those differences. Each of those is a switch you can turn off when you do mean them.

Duplicates within a list are counted and reported rather than silently collapsed — if your "unique" export has the same email three times, that is usually the most useful thing on the page.

Most ways to compare lists online want the data uploaded first. Everything here happens in your browser, so a list of customer emails does not become somebody else's data by being compared.
    Frequently asked questions
    How is this different from a diff tool?
    A diff cares about order and position — it shows you what changed where, which is what you want for two versions of a document. A list does not have an order that means anything: two exports of the same customers sorted differently are the same list, and a diff would report every single line as changed. This compares them as sets, so the answer is what is present rather than what moved. Think of it as a list diff by content rather than by position.
    Does capitalisation matter?
    Not by default, because real lists disagree about it and almost nobody means it — Alice@example.com and alice@example.com are one person. Turn "ignore case" off if the difference is genuine for your data, which it can be for passwords, IDs and case-sensitive file paths.
    What happens to the spelling in the results?
    You get back exactly what you typed. The comparison may ignore case and spacing, but the output never changes them — a list of names that came in capitalised comes back capitalised, because you are probably about to paste it somewhere that cares. Where two entries differ only by case, the one you wrote first is the one shown.
    What about duplicates inside one list?
    They are counted and reported. Only the first occurrence is used for the comparison itself, since a list containing an entry twice still just contains it — but the count is shown, because "your list of 500 unique emails has 40 duplicates" is usually more useful than the comparison you came for.
    Can I use it on CSV rows or numbers?
    Yes. It works on whole lines, so anything one-per-line compares fine: order numbers, SKUs, IDs, file paths, whole CSV rows. If you need to compare one column of a CSV rather than the whole row, split it first — our CSV to JSON tool will do that, or a spreadsheet will.
    Is my list uploaded?
    No. It runs in your browser and nothing is sent to us. That matters for the usual contents of these boxes: customer emails, employee numbers and order IDs are exactly the kind of list that should not be pasted into a stranger's server to be counted.
    How long can the lists be?
    Up to about half a million characters each, which is comfortably tens of thousands of lines. Beyond that a spreadsheet or a database is the better tool — not because this would break, but because at that size you probably want to keep the result rather than read it.
    Help improve this tool
    Found a bug, want a change, or need a tool we don't have?
    /compare-two-lists
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