GaitherDyn List Compare

Paste two lists. See what they share, what is only in A, what is only in B, the union, and the symmetric difference. Deduplicate, sort, and export. Free, runs in your browser, no account required.

How it works

  1. Paste List A into the left input and List B into the right input. One item per line.
  2. The tool computes the intersection (in both), set differences (only in A, only in B), the union, and the symmetric difference.
  3. Toggle case sensitivity and whitespace trimming to match how you want items compared.
  4. Sort and deduplicate results in place, or copy them to clipboard.
  5. Export any result set as CSV or plain text.

Features

  • Five set operations: only in A, only in B, in both, union, symmetric difference.
  • Visual Venn diagram showing the counts in each region.
  • Optional case-insensitive and trimmed comparison.
  • Deduplicate within each list before comparing.
  • Sort results alphabetically, numerically, or by original order.
  • Copy any result to clipboard, or export as CSV or plain text.
  • Runs entirely in your browser. Nothing is uploaded. No account, no tracking of your data.

Common uses

  • Reconcile two exports from different systems and find the rows that do not match.
  • Compare client rosters, caseloads, or service lists across time periods.
  • Diff email lists, contact lists, or distribution groups.
  • Audit sign-in sheets against expected attendee rosters.
  • Find rows present in a CSV but missing from a database query, or the other way around.
  • Check vocabulary lists, code lists, or category taxonomies for drift.

Frequently asked questions

Is the list compare tool free?

Yes. It is built and operated by Gaither Dynamic. No paywall and no signup.

Are my lists uploaded anywhere?

No. All comparison runs in your browser. The page does not send your list contents to any server.

How big can my lists be?

The tool handles lists with tens of thousands of items on a typical laptop. Very large lists may slow the browser depending on your device.

What is the symmetric difference?

It is every item that is in exactly one of the two lists. Items present in both are excluded. It is the union minus the intersection.

Can I compare more than two lists?

Not in a single pass. You can compare A versus B, then take the result and compare it against C.

Who built this tool?

Gaither Dynamic builds data dashboards and decision tools for Continuums of Care, local governments, and service providers. The list compare tool is part of a small network of free utilities.

Loading the list comparison tool.