ListDiff

ListDiff is a browser-based list comparison tool that helps you find what is unique to each of two lists and what they have in common. Paste items into List A and List B, or drag and drop a file onto either input box, and the tool produces four result panels: A Only, B Only, A ∩ B (in both), and A ∪ B (all items).

Key Features

• Four simultaneous result panels showing items exclusive to List A, exclusive to List B, the intersection of both lists, and the combined union.
• File upload and drag-and-drop for plain text formats including .txt, .csv, .tsv, .log, and .md, with a 5 MB limit per file.
• Normalization options such as case-insensitive comparison, ignoring leading/trailing spaces, ignoring extra spaces, and ignoring leading zeros.
• Sorting controls for both input panels and results, with alphabetical (A → Z, Z → A) and numeric (0 → 9, 9 → 0) orders.
• Multiple output formats including plain, numbered, Markdown bullets, HTML <ul> and <ol>, hashtags, JSON array, and quoted output for SQL or config files.

Typical Use Cases

• Comparing spreadsheet columns: copy two columns from Excel and paste them into List A and List B to see which values exist in one column but not the other.
• Reconciling record exports: use the A Only and B Only panels to spot items present in one database export but missing from another.
• Preparing formatted output: switch the output format to Markdown, JSON, or quoted text to reuse comparison results in documentation, code, or configuration files.
• Cleaning list data: enable whitespace and case options so that entries like "Apple" and "apple" are treated as the same item before comparing.

How It Works

1. Paste items into List A and List B, or drag and drop a supported plain text file onto either input box.
2. Adjust options such as case sensitivity, whitespace handling, leading zeros, and sort order.
3. Review the A Only, B Only, In Both, and All Items panels, choosing an output format to match how you plan to use the results.

Who It's For

ListDiff suits anyone who works with lists of values — spreadsheet users comparing columns, analysts checking database exports, and developers or writers who need clean, formatted comparison output. Its options for normalization and output formatting make it practical for both quick checks and preparing results for reuse elsewhere.

ListDiff turns a routine list comparison into a clear, formatted result with no installation or account required.