COMPARETWOLISTS.NET
How list comparison works
Compare two lists by membership: which distinct values are only in A, only in B, or in both. Every physical line is one item. Blank lines are ignored.
A worked example
Use Load example on the tool. List A contains 00123, 123, SKU-A, SKU-A on separate lines. List B contains 123, SKU-B.
With Trim outer whitespace on and Ignore case off:
| Result | Original values |
|---|---|
| Only in A | 00123 and SKU-A |
| Only in B | SKU-B |
| In both | 123 |
A has 4 valid input lines, 3 distinct values, and 1 duplicate extra row. The SKU-A group retains Input A, lines 3 and 4. It appears once in the output. This is not quantity reconciliation.
What the rules change
Trim removes outer spaces and the defined whitespace characters for matching only. Original values remain unchanged in results. Blank lines use that same rule even when trim is off.
Ignore case uses JavaScript toLowerCase() on the entire matching value. It does not promise linguistic equivalence: ß and SS do not match. Accents are not removed, and Unicode is not normalized. Leading zeros, punctuation, @ signs, text U+FEFF, and zero-width characters are preserved.
Exact whitespace and line rules
Outer whitespace: U+0009, U+000B, U+000C, U+0020, U+00A0, U+1680, U+2000–U+200A, U+2028, U+2029, U+202F, U+205F, U+3000. CRLF, CR and LF separate physical lines. One terminal newline does not create an extra placeholder line. Other trailing blank lines still count.
Original values and source lines
Each result represents the first original value in its group. In both uses A's value and A's order. Expand a result to inspect all matching variants and source lines from either input. These are current input line numbers, not row numbers from your original spreadsheet.
Copy, download and changes
Copy and TXT download include all values in the selected category, including those beyond the 100-item preview page. Outputs have one value per line and no header or added final newline. TXT is UTF-8 without an added encoding BOM.
Editing input, changing rules, swapping lists, or cancelling makes previous results unusable for export until you compare again. Both empty lists need input; a single non-empty list can be compared normally.
Limits
Each list supports up to 50,000 physical lines and 5 MiB of UTF-8 text. Import only UTF-8 TXT. Tabs trigger a choice to cancel or keep each whole line; commas never split an item. The tool cannot establish identity, explain missing entries, or restore data that a spreadsheet already changed.