Compare Two Texts
Paste an old and a new version and see exactly what changed: added lines in green, removed lines in red, and the changed words inside each line marked.
8 lines
9 lines
Differences
Word-level detail
Changed words are marked inside each line, not just the line.
Two ways to read it
Side by side for documents, inline for a compact list of edits.
Drafts stay private
Both texts are compared in your browser and never uploaded.
See every edit between two versions
A contract comes back from the other side with "a few small changes". A colleague edits your product description. A config file works on one server and not the other. In each case you need the differences, not a second read of the whole thing. Paste the original on the left and the changed version on the right, and the comparison appears below and updates as you type.
Lines are matched with the Myers difference algorithm, the same approach behind git diff. It finds the smallest set of lines to remove and add to turn one text into the other, which keeps unchanged lines lined up even when whole paragraphs were inserted. With Words selected, each changed line is paired with its new version and the words that differ are marked, so a single changed number in a long sentence is easy to spot.
Because the comparison starts from lines, the way each text is broken into lines matters. If one version has a whole paragraph on each line and the other is wrapped at 80 characters, nearly every line will look different. Run both through Remove Line Breaks with Keep paragraphs first and the real edits stand out again.
How to use it
- 1Paste the original text on the left and the changed text on the right.
- 2Choose Lines or Words, and Side by side or Inline.
- 3Turn on Ignore case or Ignore whitespace if those differences don't matter.
- 4Read the counts and the highlighted changes; use Only changes for long texts.
Reading the result
- Side by side shows the original on the left and the changed text on the right, with line numbers from each. A removed line has a red background, an added one green, and a line that exists on one side only leaves an empty grey cell on the other.
- Inline shows one column. Lines starting with - were removed and + were added. In Words mode a changed line appears once, marked ~, with deleted words struck through in red and new words in green.
- The counters count lines: a line that was edited counts as one removed and one added.
Ignore options
Ignore case treats "Hello" and "hello" as equal. Ignore whitespace treats any run of spaces or tabs as a single space and ignores spaces at the start and end of a line, so re-indented code or text with double spaces after full stops doesn't show up as changed. It doesn't ignore spaces entirely: "ice cream" and "icecream" still differ.
Ignored differences are only ignored for matching. The text you see is always your own, exactly as pasted.
Long documents
A few thousand lines on each side compare quickly, and the work runs in the background so the text boxes stay responsive. Each side can have up to 20,000 lines; above that the tool asks you to split the text into parts. The view draws at most 10,000 rows, and Only changes hides unchanged stretches, keeping 2 lines of context around every change, which is the easiest way to read a long diff.
When two texts are almost entirely different, finding the smallest possible diff would take a long time. In that case the tool stops searching for the fine detail in those stretches and shows them as a block removed and a block added, with a note saying so.
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What Our Users Say
Real feedback from people using WeblixTools, checked by our team before it appears.
5.0 out of 5 · 1 review
very nice
Frequently Asked Questions
How do I compare two texts for differences?
Paste the first version in Original text and the second in Changed text. Differences show up straight away below: green for added, red for removed. Pick Words to see exactly which words changed inside a line.
What's the difference between Lines and Words?
Lines marks whole lines as removed or added. Words does the same line matching, then compares each removed line with the added line next to it and highlights only the words that differ. Words is better for prose, Lines for code and lists.
Can I ignore spaces and capital letters?
Yes. Ignore case makes capitals irrelevant, and Ignore whitespace treats several spaces as one and ignores spaces at line ends. Both only affect matching, not the text shown.
Why is a moved paragraph shown as removed and added?
A line-based diff only knows about removing and adding. If a paragraph moves from the top to the bottom, the shortest way to describe it is one removal and one addition, which is what you see.
How long can the texts be?
Up to 20,000 lines on each side. A few thousand lines compare in well under a second on a typical computer. For longer texts, turn on Only changes so only the edited parts are drawn.
Can I compare code or JSON?
Yes. The text boxes use a monospaced font, and Lines with Ignore whitespace works well for code that was re-indented. There's no syntax colouring.
Why is a whole line marked when I changed one letter?
In Lines mode the smallest unit is a line, so any change marks the whole line. Switch to Words and only the changed word is highlighted, with the rest of the line shown normally.
Are my texts uploaded?
No. The comparison runs in your browser and nothing is sent to us, so it's fine for drafts, contracts and private notes.