List Diff — Compare Two Lists & Find Differences
The fastest free list diff tool online. Paste two lists or upload .txt / .csv files to instantly see the list difference: items only in A, only in B, their intersection, and their union. No sign-up. Zero data stored.
All list diff processing runs locally in your browser — your lists are never uploaded or stored.
What Is List Diff?
A <strong>list diff</strong> compares two lists of items and identifies their differences. Unlike a standard text diff that works line-by-line on documents, a list diff treats each entry as an independent unit and performs set operations — showing you exactly what belongs to List A only, List B only, both lists (intersection), or either list (union). Use our free <strong>listdiff</strong> tool to spot the list difference in seconds.
Paste or Upload Files for List Diff
Type or paste your items directly, one per line — or click Upload Files to import a .txt or .csv file for each list. The list diff engine parses your data instantly so you can compare list differences without manual formatting.
Instant List Difference Results
Our list diff tool computes results in real time as you type. No button click needed — the list difference is always up to date. Results are organized into four clear sets: A Only, B Only, Intersection (A∩B), and Union (A∪B).
Four Output Formats for Every Workflow
Export your list diff results as plain text, a numbered list, an HTML unordered list, or a unified diff (the code-style format used by Git and patch tools). The diff list output adapts to your downstream tool — spreadsheet, database, or code review.
100% Private — List Diff Runs in Your Browser
Every list diff calculation happens locally in your browser. Your data never leaves your device, which means your lists stay completely private — ideal for sensitive SKUs, email addresses, or confidential records.
How to Use List Diff in 3 Steps
Run a complete list diff in under a minute — no account, no installation required.
Step 1 — Paste or Upload Your Two Lists
Paste your items into List A and List B (one item per line), or click Upload Files to import a .txt or .csv file for either side. Configure the delimiter, preview the parsed items, and confirm. The list diff starts computing immediately.
Step 2 — Review List Diff Results in Real Time
The list diff results update live as you type. Switch between four tabs: A Only (items not in B), B Only (items not in A), Intersection A∩B (shared items), and Union A∪B (all unique items combined). Each tab shows an item count so you can track the list difference at a glance.
Step 3 — Copy, Download, or Switch for Iterative Diff
Copy the formatted results to your clipboard or download as a .txt or .diff file. Use the Switch buttons to push any result set back into List A or List B for iterative list diff — perfect for multi-round deduplication or progressive data cleaning.
List Diff Features
Everything you need to find the list difference between two lists — fast, flexible, and completely free.
Real-Time List Diff — No Button Needed
Results update instantly as you type. Our list diff engine uses efficient set operations so even large lists produce a live list difference with no noticeable lag.
Four Set Operations
Every list diff produces four distinct result sets: A Only, B Only, Intersection (A∩B), and Union (A∪B) — giving you a complete picture of the list difference in one view.
Case-Sensitive List Diff Toggle
Switch between case-sensitive and case-insensitive list diff matching with one click. Useful when comparing email addresses (case-insensitive) versus programming tokens (case-sensitive).
Normalize: Trim, Blank Lines, Leading Zeros
Strip leading/trailing whitespace, remove blank lines, and strip leading zeros before running the list diff. Normalizing data first produces a cleaner list difference and eliminates false positives.
Upload .txt and .csv Files
Import up to 2 MB per file directly into the list diff tool. Supports common delimiters — newline, comma, semicolon, tab, or a custom character — so any export from Excel or Google Sheets works immediately.
Four Output Formats
Export list diff results as plain text, a numbered list, an HTML snippet ready for your CMS, or a unified diff formatted like a Git patch. Choose what works best for your workflow.
One-Click Copy and Download
Copy any list diff result set to your clipboard with one click, or download it as a text or diff file. The formatted output applies your chosen format so the list difference is ready to paste anywhere.
Switch Results for Iterative List Diff
Push any result set back into List A or List B using the Switch buttons. Re-run the list diff against a new list or refine the results progressively — ideal for multi-step data reconciliation.
Frequently Asked Questions
Common questions about list diff, list difference, and listdiff tools.
Start Your List Diff Now
Paste your lists above and see the list difference in real time — completely free, no sign-up required. Whether you call it a list diff, a listdiff, or a diff list, our tool has you covered.