Online List Diff & Set Comparator — Compare Two Lists (A ∩ B, A − B, A ∪ B)

Instant Set Logic, Venn Intersection, Deduplication & Line Diff in Browser

Zero-Upload Set Engine
List A (Baseline Set)
7 unique1 dups
Set A · UTF-8
List B (Comparison Set)
7 unique1 dups
Set B · UTF-8
Computed Set Output
4 lines
Export Set

How to Compare Two Lists & Compute Set Operations

  1. Paste or drop line-separated items, CSV columns, emails, domains, or IDs into List A and List B.
  2. Toggle normalization rules (Trim Spaces, Ignore Case, Skip Empty, Sort A→Z) to standardize keys before comparison.
  3. Click any set operator (A ∩ B, A − B, B − A, A ∪ B, A Δ B) or Venn region to inspect and export the resulting list as TXT, CSV, or JSON.

Guide

How do the 5 set operations (A ∩ B, A − B, B − A, A ∪ B, A Δ B) work?

Intersection (A ∩ B) returns elements present in both lists. Difference (A − B or B − A) isolates elements exclusive to one list. Union (A ∪ B) merges all unique items from both lists, and Symmetric Difference (A Δ B) returns items that appear in either List A or List B, but never both.

How does deduplication, case sensitivity, and sorting work?

ListDiff.net hashes every line into an in-memory Set. Enabling Ignore Case matches uppercase and lowercase variants while preserving the original casing of the first occurrence. Duplicate counts are tracked automatically per list.

Are my lists, emails, or database keys uploaded to any server?

No. ListDiff.net executes all set comparisons, hashing, and exports 100% locally in your browser memory using JavaScript Set and Map structures. Your data never leaves your device.