Compare two lists online
Paste List A and List B, then compare instantly. Processing stays local in your browser.
Tool
How it works
- Paste two lists, upload .txt/.csv, or click Example to load a built-in preset.
- Choose options for split, spaces, case, and empty lines.
- Click Compare lists and review the result tabs.
- Copy results or download as
.txt/.csv.
Best use cases
- Compare text, numeric IDs, and mixed tokens as one-item-per-line datasets.
- Handle Excel/TSV paste with optional line splitting by delimiters.
- Copy from local files and compare without any account connection.
- Compare followers vs following style lists with explicit A/B mapping.
Quick answers
What does A only mean? Items found in List A but not in List B.
Why can counts differ? Text lines include blank lines, while keys are normalized unique items.
When should I use CSV first-column mode? Use it when each row has multiple fields but you only compare one identifier column.
What is ListDiff?
ListDiff is a browser-local list comparison tool for practical reconciliation work. It helps you compare two sources and split the output into actionable buckets: A only, B only, Intersection, Union, and Symmetric difference.
This workflow is useful when you need to check what is missing, what is extra, and what is matched between exports from spreadsheets, business systems, or social-platform data dumps. Because processing is local in your browser, you can iterate fast on options without waiting for server-side jobs.
A only / B only
Use these tabs for mismatch actions. They answer “what exists in one source but not in the other.”
Intersection
Use this tab as overlap evidence. It helps validate shared records before exporting final action lists.
Duplicates tabs
Use duplicate diagnostics to detect source-quality issues before final reconciliation decisions.
When this tool is the right choice
- Comparing two identifier lists (users, SKUs, emails, codes) with clear one-item-per-line semantics.
- Reconciling expected vs actual exports where both sides can be normalized into plain text or CSV.
- Preparing mismatch files for manual operations and audit-friendly reporting.
- Checking followers/following style lists without connecting third-party accounts.
Featured guides and use cases
FAQ
Do you upload my lists?
No. Comparisons are executed locally in your browser. See Privacy.
Why is my intersection empty?
Usually whitespace, casing, empty lines, or delimiter settings. Try toggling Ignore leading/trailing spaces and review Excel paste.
Is this related to Instagram follower tools?
ListDiff is a generic list comparison utility. If you can export names/IDs to text, you can compare them here—without connecting any third-party account.
What file formats can I compare?
You can paste plain text, import .txt, and import .csv
with row or first-column parsing mode.
What does symmetric difference mean?
It means items that exist in exactly one list, combining A-only and B-only results in one view.
Can I use this for reconciliation tasks?
Yes. It is suitable for list cleanup, ID reconciliation, and mismatch analysis when both sources can be represented as line-based lists.