Free Online List Diff - Compare Two Lists Instantly
Instantly compare two lists and find differences, matches, and unique items with our free online list comparison tool. Whether you need to compare lists for data analysis, reconciliation, or deduplication, our list diff tool makes it easy.
100% private and secure — all list comparison happens directly in your browser. No uploads, no servers, no tracking. Perfect for comparing email lists, inventory data, spreadsheet columns, or any line-by-line data.
Why Use This List Comparison Tool?
Unlike spreadsheet formulas or manual comparison, our online list diff tool shows all set operations instantly — unique items, common items, union, and symmetric difference in one view.
Instant Results
See differences as you type — no button clicks needed. Compare lists online in real-time with immediate visual feedback for all five set operations.
100% Private
Your data never leaves your device. Unlike other list comparison tools, we don't upload your lists to any server. Compare sensitive data with complete privacy.
Five Set Operations
Get unique items in A, unique in B, union, intersection, and symmetric difference — all calculated simultaneously. Complete list analysis in one tool.
Flexible Options
Case sensitive or insensitive comparison, trim whitespace, ignore leading zeros, normalize spaces. Customize how items are matched to fit your data.
Export Results
Download any result as a text file or copy to clipboard instantly. Sort output A-Z or Z-A, add line numbers, convert case — format results your way.
No Sign-up Required
Start comparing immediately — no registration, no email, no accounts. This free list diff tool respects your time and privacy from the first click.
Understanding List Set Operations
Our tool performs five essential set operations to help you compare two lists comprehensively.
Only in A
Items that exist only in List A and not in List B. Use this to find what's missing from the second list.
Only in B
Items that exist only in List B and not in List A. Use this to find what's been added or is unique to the second list.
Union (A ∪ B)
All items from both lists combined, with duplicates removed. The complete set of unique items across both lists.
Intersection (A ∩ B)
Items that appear in both lists — the common elements. Use this to find matches and duplicates across lists.
Symmetric Diff (A △ B)
Items in either list but not both — the opposite of intersection. Shows all differences between the two lists.
Common Use Cases
Our list comparison tool handles any line-by-line data. From spreadsheet columns to database exports, email lists to inventory — if it's a list, you can compare it.
Excel & Spreadsheets
Compare two lists in Excel without complex formulas. Copy columns from your spreadsheet, paste here, and instantly see differences.
- Compare spreadsheet columns
- Find missing rows between sheets
- Cross reference two lists
- Reconcile data exports
- Match inventory lists
Data Analysis
Find duplicates, unique items, and matches between datasets. Perfect for data cleaning, deduplication, and reconciliation tasks.
- Find duplicates in two lists
- Remove duplicates from output
- Compare email lists
- Match customer IDs
- Reconcile database records
Development
Compare arrays, config values, or any line-based data. Get the same results as Python set operations without writing code.
- Compare array values
- Diff config file entries
- Match API response items
- Compare package lists
- Verify deployment configs
How to Compare Two Lists Online
Using our online list comparison tool is simple. Follow these steps to find differences between your lists:
Enter List A
Paste or type your first list in the List A editor — one item per line.
Enter List B
Paste or type your second list in the List B editor for comparison.
View Results
Instantly see all five set operations — unique items, matches, union, and more.
Export
Copy results to clipboard or download as text files. Sort and format as needed.
Pro tip: Use "Trim Whitespace" to ignore leading/trailing spaces in your items.
Enable "Case Sensitive" off to treat "Apple" and "apple" as the same item.
Compare Lists in Python
Developers often need to compare two lists in Python. Here's how our tool's operations translate to Python set operations:
# Python: Compare two lists list_a = ['Apple', 'Banana', 'Cherry'] list_b = ['Banana', 'Cherry', 'Date'] only_a = set(list_a) - set(list_b) # Only in A only_b = set(list_b) - set(list_a) # Only in B union = set(list_a) | set(list_b) # Union intersection = set(list_a) & set(list_b) # Intersection symmetric = set(list_a) ^ set(list_b) # Symmetric diff
Our online tool provides the same functionality without writing code — perfect for quick comparisons or when you need to find the difference between two lists without a development environment.
Frequently Asked Questions
How do I compare two lists online?
Simply paste your first list in List A and second list in List B — one item per line. Results appear instantly showing unique items, matches, union, intersection, and symmetric difference.
Can I compare lists from Excel?
Yes! Copy a column from Excel and paste it directly into List A or List B. Our tool handles the line breaks automatically. Much faster than using VLOOKUP or MATCH formulas.
Is this list comparison tool free?
Yes, completely free with no sign-up required. All features including export, sorting, and formatting options are available at no cost for personal and commercial use.
Is my data secure?
Absolutely. All comparison happens in your browser — your lists are never uploaded to any server. You can even use this tool offline once the page loads.
How do I find duplicates between two lists?
The 'Intersection' result shows items that appear in both lists — these are your duplicates or matches. Use this to find common items across your datasets.
Can I ignore case when comparing?
Yes! Uncheck 'Case Sensitive' in the options to treat 'Apple' and 'apple' as the same item. You can also trim whitespace and ignore leading zeros.
How do I export the results?
Each result panel has Copy and Download buttons. Click Copy to copy to clipboard, or Download to save as a .txt file. You can also sort and add line numbers before exporting.
What's the difference between Union and Symmetric Difference?
Union includes ALL items from both lists. Symmetric Difference includes only items that are in one list OR the other, but NOT both — it excludes the common items.