Compare Two Lists
Paste two lists and instantly see only-in-A, only-in-B, and shared items with counts.
About this tool
Compare Two Lists treats each of your two lists as a set and tells you exactly how they overlap: which items are only in List A, which are only in List B, and which are shared by both — each section with a count, followed by a totals line that also reports the union size. It's the fast way to reconcile two exports of anything: email subscribers, customer IDs, SKUs, domains, package names, or feature flags.
Everything runs locally in your browser — nothing is uploaded.
Worked example
List A
apple
banana
cherry
List B
banana
cherry
date
Comparison
Only in A (1):
apple
Only in B (1):
date
In both (2):
banana
cherry
Totals: A=3 · B=3 · only in A=1 · only in B=1 · in both=2 · union=4
apple is unique to A, date is unique to B, and banana/cherry appear in both.
Options
- Separator — split each list by new line (default), comma, tab, semicolon, pipe, or space.
- Ignore case — treat
Appleandappleas the same item. - Trim whitespace — strip leading/trailing spaces before comparing (on by default).
- Ignore blank items — drop empty lines (on by default).
- Remove duplicates — collapse repeats within a list so it behaves as a true set (on by default; turn it off to keep every occurrence).
- Ignore leading zeros — match
007with7, handy for numeric IDs. - Sort order — keep the input order (default), or sort each section A→Z or Z→A.
Limits
- Up to 100,000 items per list.
- The item text you paste is compared as-is (after the options above) — there is no fuzzy or
partial matching;
appleandapplesare different items. - The displayed item keeps List A's original form when the same item is shared (so with
Ignore case on, a shared
[email protected]shows A's capitalization).
FAQ
What is the difference between "only in A", "only in B", and "in both"?
Only in A are items present in your first list but missing from the second. Only in B are items in the second list but missing from the first. In both are the items the two lists share (the intersection). Together they make up the union, whose size is shown on the totals line.
How do I compare comma-separated or tab-separated lists?
Change the Separator dropdown to Comma, Tab, Semicolon, Pipe, or Space. Both lists
are split the same way, so paste them in whatever format you have — one item per line is the
default.
Does it ignore duplicates and blank lines?
By default yes. Remove duplicates collapses repeated items within each list so the comparison
uses set semantics, and Ignore blank items drops empty lines. Turn Remove duplicates off
if you want every occurrence listed instead. Note the totals counts are always unique-set based,
so union always equals only in A + only in B + in both.
Can it match items that differ only by case or leading zeros?
Yes. Enable Ignore case to treat Apple and apple as the same item, and Ignore leading
zeros to treat 007 and 7 as equal — useful for reconciling numeric IDs, order numbers, or
SKUs that were exported with different zero-padding.
Is my data uploaded anywhere?
No. The comparison runs entirely in your browser via WebAssembly — your lists never leave your device.
Developer & Automation Access
Run it from the terminal
Same engine as this page, headless — via the gizza CLI:
gizza tool list-set-diff "apple
banana
cherry" 'list_b=banana
cherry
date'New to the CLI? Get gizza →
Open it by URL
Pre-fill and auto-run this tool with query parameters — the names match the API/CLI:
https://gizza.ai/tools/list-set-diff/?list_a=apple%0Abanana%0Acherry&list_b=banana%0Acherry%0Adate&separator=newline&ignore_case=true&trim=true&ignore_blank=true&dedupe=true&ignore_leading_zeros=true&sort=inputMachine-readable descriptor: tool.json — title + parameters JSON Schema for agents.