Text & List Tools · runs locally

Longest Common Subsequence Finder

Find the longest ordered grapheme sequence shared by two texts even when matching characters are separated by gaps.

Result

Ready. Your working data stays in this browser.

Why this tool is useful

Use an LCS to compare ordered revisions, study retained symbols or explain why two values resemble each other despite inserted material.

The browser builds a bounded length matrix and backtracks through equal graphemes to reconstruct one deterministic longest subsequence.

AGGTAB and GXTXAYB share GTAB in order, giving an LCS length of 4.

The calculation is deterministic and explains validation errors instead of silently changing invalid input.

Input and output remain in this tab. Copy and download happen through browser APIs without a server upload.

Every run reports its tool mode, timestamp and input/output size so transformed data can be audited.