Text Diff Checker — Compare Two Texts
Paste the original text on the left and the edited version on the right. The checker compares them line by line — additions in green, removals in red — and inside lines that were edited rather than wholly replaced, it highlights the exact words that changed.
Differences
Paste both versions above to see what changed, line by line.
Present the changes in Moda
Build a before/after slide or annotated review doc from the revision you just verified.
Try Moda free →How the comparison works
The checker computes a longest-common-subsequence diff — the same family of algorithm behind git and code-review tools. It finds the largest set of lines the two versions share in the same order, and everything outside that set is marked added or removed. This is why a moved paragraph shows as a removal in one place and an addition in another: the algorithm tracks content and order, and a move genuinely is both of those changes.
Word-level highlighting inside changed lines
When a removed line and an added line sit in the same changed block, they are treated as two versions of one line and diffed again at word level — so a one-word edit in a long sentence shows one highlighted word, not two walls of red and green. Pairing is positional (first removed with first added, and so on), which reads correctly for normal editing; refinement is skipped on extremely long lines and rationed across very large changes to keep the page fast — those lines keep their whole-line coloring, which still shows what changed.
Line endings, whitespace, and size limits
Windows (CRLF) and Unix (LF) line endings are normalized before comparing, so a file that round-tripped through a different OS does not light up as fully changed. Whitespace inside lines is significant — a double space is a real difference, and the word-level highlight will pin it down. Inputs are capped at 3,000 lines per side because the comparison is quadratic in the worst case; beyond that the tool tells you to split the text rather than freezing your tab.
Frequently asked questions
Are the differences case-sensitive?
Yes. "Hello" and "hello" are different lines, and within a changed line the word-level highlight will mark exactly the capitalization change. There is no ignore-case mode.
Why does a moved paragraph show as deleted and added?
The diff tracks lines in order, and a paragraph that moved genuinely disappeared from one position and appeared in another. Move detection is a heuristic layered on top by some tools; this checker reports the raw, unambiguous picture.
Can I diff code with this?
Yes — the algorithm is the same one code tools use, lines are compared exactly, and indentation changes show up. You just won’t get syntax highlighting or unified-patch output, so for reviewing commits your editor or git remains the better home.
Is my text uploaded anywhere?
No. Both texts are compared entirely in your browser with no network requests, so contracts and unpublished drafts are safe to paste.
What do the +/− counts above the result mean?
The number of whole lines added and removed. An edited line counts once on each side — its old version as removed, its new version as added — even when only one word inside it changed.