COMPARETWOLISTS.NET
Compare two columns copied from Excel
Use this workflow when you already have two single columns in Excel or Google Sheets and want to see which identifiers are missing or shared.
1. Copy one column into each list
Exclude headers and select cells without internal line breaks. Copy the first column into List A and the second into List B. Do not copy multiple columns. If tabs are detected, cancel and copy one column again, or explicitly keep every entire line as a single value.
This tool accepts pasted text and UTF-8 TXT. It does not upload or parse XLSX, CSV, or TSV files.
2. Check the rules and compare
For a reproducible example, paste these four lines into A:
00123
123
SKU-A
SKU-A
Paste these two lines into B:
123
SKU-B
Keep Trim outer whitespace on and Ignore case off, then choose Compare lists.
3. Read the answer
Only in A contains 00123 and SKU-A. Only in B contains SKU-B. In both contains 123. SKU-A has two source lines but only one distinct value. This answers membership, not how many units are missing.
4. Copy back as text
Choose the result category, then Copy all values or Download TXT. Before pasting identifiers, format the destination spreadsheet column as Text. For TXT, use your spreadsheet's text import options and select a text column type.
The browser preserves strings, but your spreadsheet may still convert leading zeros, long identifiers, dates, or formula-like text. Check a few cells after pasting. Opening TXT directly does not guarantee preservation in every spreadsheet. This guide does not claim a tested round trip in every Excel version.
What source lines mean
If you copied from Excel row 201, the first pasted item is still Input A, line 1 here. Display wrapping does not create extra input lines.