What do the colours mean?

Removed text is shown in red with a line through it, and added text in green with an underline, so the difference is clear even without colour. In the side-by-side view, removed text appears in the original column and added text in the changed column.

Should I compare by word, line or character?

Word mode is best for articles, captions and documents, because it shows exactly which words changed. Line mode suits code, CSV files and lists, where a whole line is the unit of change. Character mode catches tiny edits such as a changed letter, a missing comma or a swapped digit.

What does ignore whitespace do?

It treats any run of spaces, tabs and line breaks as the same, and ignores spaces at the start and end of lines. Use it when one version was re-indented or reflowed and you only care about changes to the words.

What is a unified diff?

It is the standard text format used by Git and the diff command. Removed lines start with a minus sign, added lines with a plus sign, and each block of changes is introduced by a line such as @@ -4,6 +4,7 @@ that gives the line numbers. You can paste it into a code review, a ticket or an email, or apply it with a patch tool.

How large can the texts be?

Several megabytes is fine for texts that are mostly the same. The tool uses the Myers diff algorithm, which is fast when there are few changes. When two large texts are almost completely different, it limits the work, shows the affected part as one removed and one added block, and tells you it did so.

Are my texts uploaded?

No. The comparison runs entirely in your browser. Neither text is sent to a server or stored.

Diff Checker

Compare two versions of a text and see exactly what was added, removed or changed. Compare by word, line or character, side by side or inline.

100% free
No sign-up
Runs in your browser

Original text

173 characters · 30 words · 4 lines

Changed text

212 characters · 38 words · 5 lines

Ignore caseIgnore whitespace

+ 13 words added− 3 words removed

Original

Hi! Thanks for your comment. Here is the link to our spring collection: example.com/spring Reply to this message if you have any questions. Free shipping on orders over $50.

Changed

Hi! Thanks so much for your comment. Here is the link to our summer collection: example.com/summer Reply to this message if you have any questions. Use code SUMMER10 for 10% off. Free shipping on orders over $40.

removed removed textadded added text

When a diff checker saves you time

Reading two versions of a document side by side and hunting for changes is slow, and small edits are easy to miss: a price that changed from $50 to $40, a removed sentence in a contract, a link that now points somewhere else. A diff checker finds every one of them in a second.

Check what a client or colleague changed in a caption, blog post or email before you publish it.
Compare two versions of an auto-reply or DM template to make sure only the offer changed.
Review edits to code, configuration files, CSV exports or lists of links.
Spot differences between a draft and the text that is actually live on a page.

How the comparison works

The tool uses the Myers diff algorithm, the same approach behind Git, which finds the smallest set of insertions and deletions that turns the original into the changed text. It first lines up matching lines, then compares each changed block word by word or character by character, depending on the mode you pick.

Reading the result

Removed text is red with a strikethrough and added text is green with an underline. A changed word shows up as one removal followed by one addition. The counts at the top tell you how many words, lines or characters were added and removed in total.

How it works

How to use it

Step 1
Paste both versions
Put the original text on the left and the changed text on the right. The comparison updates as you type.
Step 2
Choose how to compare
Compare by word for edited prose, by line for code, lists and data, or by character for small typo fixes.
Step 3
Review and copy
Read the changes side by side or inline, then copy or download a standard unified diff if you need to share it.

FAQs

Frequently asked questions

Answers to common questions about the Diff Checker.

: Removed text is shown in red with a line through it, and added text in green with an underline, so the difference is clear even without colour. In the side-by-side view, removed text appears in the original column and added text in the changed column.
: Word mode is best for articles, captions and documents, because it shows exactly which words changed. Line mode suits code, CSV files and lists, where a whole line is the unit of change. Character mode catches tiny edits such as a changed letter, a missing comma or a swapped digit.
: It treats any run of spaces, tabs and line breaks as the same, and ignores spaces at the start and end of lines. Use it when one version was re-indented or reflowed and you only care about changes to the words.
: It is the standard text format used by Git and the diff command. Removed lines start with a minus sign, added lines with a plus sign, and each block of changes is introduced by a line such as @@ -4,6 +4,7 @@ that gives the line numbers. You can paste it into a code review, a ticket or an email, or apply it with a patch tool.
: Several megabytes is fine for texts that are mostly the same. The tool uses the Myers diff algorithm, which is fast when there are few changes. When two large texts are almost completely different, it limits the work, shows the affected part as one removed and one added block, and tells you it did so.
: No. The comparison runs entirely in your browser. Neither text is sent to a server or stored.

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