Data

Text Diff

Details

How to use Text Diff

What the tool does, how to run it, and what to expect from the result.

How to compare two texts

To compare two texts, paste your original block on one side and the changed block on the other, and the Text Diff tool computes a line-by-line comparison. Changed lines are flagged, and within them inline word highlights show the precise additions and deletions so nothing is missed.

Because the Text Diff tool runs client-side in your browser, both blocks stay on your device and are never uploaded. That makes it safe for comparing drafts, code snippets, contracts, or any sensitive text, with no signup required.

  • Paste the original and changed text
  • See line-level additions and removals
  • Read inline word highlights in changed lines
  • Copy the diff summary

What Text Diff is built for

The Text Diff tool focuses on showing exactly what changed in the source text itself, which keeps the interface simple and avoids rendered-format noise. It is ideal for proofreading edits, reviewing copy changes, and spotting small differences between two versions.

It is a compare-and-inspect tool rather than a merge editor, so it highlights differences instead of combining the two sides. That narrow scope keeps the diff clear and easy to scan, and the inline word highlights make even single-character edits obvious.

Tips

Getting a better result out of Text Diff

Specific settings and thresholds, not general advice.

  • The diff is line-first. When a removed block is immediately followed by an added block, the two are compared again word by word and the changed words are highlighted inside the line, so you see what changed rather than that the line changed.
  • Line endings are normalized on both sides before the comparison, so a file that differs only in CRLF versus LF shows as no change at all. That is a feature: it stops a whitespace-only diff drowning the real one.
  • Trailing spaces are not normalized, so a line with a trailing space is a different line. If everything shows as changed, check for trailing whitespace and clean both sides with Remove Extra Spaces first.
  • A block that was moved rather than edited shows as a removal in one place and an addition in another. The diff has no concept of a move.
  • The summary counts added lines, removed lines and changed blocks. A changed block is a contiguous run of edits, so a single reworded paragraph counts as one block, not as ten lines.
Limits

What Text Diff does not do

The honest boundary, so you do not lose time finding it yourself.

  • Two text blocks only. There is no three-way diff and no merge.
  • It compares pasted text, not files or URLs.
  • Moved blocks are reported as a deletion plus an addition.
  • There is no ignore-whitespace or ignore-case option.
At a glance

Who Text Diff is for

A quick way to understand who this helps, what it solves, and where it connects next.

Best fit

Founders, docs writers, SEO teams, developers, and operators checking pasted text changes quickly.

Ideal for

Comparing copy, docs, notes, snippets, or lists when you need something lighter than a full diff app.

FAQ

Common questions

Short answers for the questions people usually have before trying a utility like this.

Does it show word-level changes inside changed lines?

Yes. Changed lines get inline word highlights so you can see the precise words that were added or removed, not just which lines differ.

Does it upload my text?

No. The Text Diff tool runs entirely in your browser, so both text blocks stay on your device and are never uploaded.

Is this a merge tool?

No. It is a compare and inspection page that highlights differences, not a merge editor that combines the two versions.

Is it free to use?

Yes. The Text Diff tool is free with no signup and runs fully in your browser.

Does it show what changed inside a line?

Yes, when the change is an edit rather than a pure insertion or deletion. If a removed line is immediately followed by an added one, the tool runs a second, word-level comparison over the pair and highlights only the words that differ. That is what turns a wall of red and green into a readable edit.

Why does my whole document show as changed?

Almost always whitespace. A trailing space on every line, or an indentation change, makes every line a different string. Line endings are not the cause, because CRLF and LF are normalized before the comparison. Run both sides through Remove Extra Spaces and diff again.

Will a CRLF file diff cleanly against an LF file?

Yes. Both inputs have their line endings normalized before anything is compared, so a text that differs only in its line-ending convention produces an empty diff. This is deliberate, since a line-ending-only diff is noise in almost every situation.

What does the changed blocks number mean?

It counts contiguous regions of change, not individual lines. A paragraph that was rewritten counts as one block even if it spans ten lines, and two edits in different parts of the document count as two. It is a better measure of how much a text actually changed than the raw line counts are.

Can I use it to merge the two versions?

No. This is a comparison tool, not a merge editor. It shows you what differs and lets you copy a summary of the counts. Applying the changes is something you do in your own editor.

Is my text uploaded?

No. The diff is computed in the page, so you can compare two versions of a contract, a config or an unpublished draft without any of it leaving the browser.

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