Difference Checker
Compare two texts and the difference get's highlighted.
Tool guide
About Text Difference Checker
The Difference Checker compares an original text with a modified version and highlights words that were added or removed. It is useful for reviewing edits, but the comparison follows text differences rather than meaning, so a rewrite can appear as many separate changes.
Difference Checker places an original text and an edited version side by side, then marks what changed in a combined result. Additions appear in green and removed text appears in red with a strike-through. The comparison is based on words and their sequence, so it can show what changed but cannot tell whether an edit is correct or better.
How to use this tool
- 1Paste the earlier version into the original text field.
- 2Paste the revised version into the second field. Keep headings and punctuation if you want them included in the comparison.
- 3Review the highlighted additions and removals from top to bottom. Copy the source texts elsewhere before making edits if you need a record.
Main features explained
01Two editable source fields
Paste the earlier version into Original Text and the later version into Changed Text. The result updates from those two inputs, so make sure the correct versions are in the correct panels before interpreting the colors.
02Word-level comparison
The page uses the `diffWords` function from the diff library. It compares word-like segments and surrounding text rather than document formatting, page layout, or meaning.
03Added and removed highlights
Added portions use green text on a green-tinted background. Removed portions use red text, a red-tinted background, and a line through the old wording. Unchanged sections remain in the output without a change mark.
04Live updates and clear action
A memoized comparison is recalculated as either text changes. Clear empties both source fields. The page does not create a downloadable report or save a revision history, so keep your own copies when needed.
How it works
The page compares the two entered strings at the word level and displays the differences between them. Word-based comparison can make a moved phrase appear as a removal in one place and an addition in another, even when its wording is unchanged.
A quick example
Changing `The blue box is small` to `The blue box is compact` highlights `small` as removed and `compact` as added. The tool does not judge whether the new sentence is clearer.
Worked examples
One word changed
Before
Original: The blue box is small. Changed: The blue box is compact.
After
Removed: small Added: compact
The unchanged words remain visible around the removed and added portions, so you can see the edit in context.
A moved phrase
Before
Version A: Bring a coat and hat. Version B: Bring a hat and coat.
After
May show a removal and an addition
A word diff can represent moved text as deletion in one position and insertion in another; it does not label a move as a special operation.
When it is useful
Review draft edits, compare copied code comments, check policy text, and spot changed wording in notes or simple documents.
Reviewing a short edit
Compare two versions of a paragraph, email, policy note, or description to spot a changed phrase before sending or publishing it.
Checking a wording change
Use the highlights to find the exact words that were replaced. Then read the full sentence, because the tool does not judge grammar, facts, tone, or legal effect.
Comparing copied snippets
Check a small block of plain text from two documents or messages. Paste only the relevant section if a large document produces a crowded result.
Reviewing code comments or text configuration
A word-level comparison can reveal changed comments and values, but it does not understand syntax, whitespace significance, or whether the program still works. Use a code-aware diff for source files.
Tips for a better result
- Put the earlier version in Original and the newer version in Changed so the color direction is easy to understand.
- Compare similar-sized sections when possible. A complete rewrite can create many highlights that are hard to scan.
- Read a few words before and after each highlight. The changed word alone may not show whether the sentence still makes sense.
- Keep both source versions elsewhere if you need a permanent audit trail; the page does not save comparison history.
- Use a specialized document or code comparison tool when formatting, line numbers, or syntax are important.
Technical details and limits
The diff does not understand intent, formatting, tracked changes, tables, or semantic equivalence. Large edits can produce dense highlights. Sensitive material should be handled according to your organization's privacy requirements.
The result depends on the text and options you provide. Keep a copy of the original when formatting matters, and review the output before using it in a document, site, or application. This guide describes the tool's behavior; it does not replace proofreading or checking a platform's own requirements.
Frequently asked questions
Does it compare meaning or exact wording?
It compares text changes, not meaning or factual correctness.
Why are moved words shown as changed?
A word-level diff may represent a move as deletion and insertion.
Can it compare Word document formatting?
It compares pasted text and does not preserve document styles or layout.
What do the colors mean?
Green highlights text added in the changed version. Red strikethrough text was present in the original and is now removed.
Does the checker tell me which version is correct?
No. It marks text differences but does not fact-check or judge writing quality.
Why are moved words shown as removed and added?
The comparison follows sequence. A moved phrase may be represented as a deletion at its old position and an addition at its new one.
Does it compare Word formatting, images, or tables?
No. The inputs are plain text, so document styles, tables, and images are not part of the result.
Why does a full rewrite show so many differences?
Word-level algorithms compare shared wording and order. If little text is shared, much of the new version appears as added and removed content.
Does the page save my comparison?
No. Keep copies of important text separately before clearing or leaving the page.