Can I compare any kind of text?

Yes. Paste prose, code, configuration, logs, or any other text. The diff algorithm works on lines and words, so it handles any content your browser can display.

How accurate is the comparison?

The diff uses a longest common subsequence algorithm on lines, then highlights the words that differ inside each changed line. Within the size limits every changed line is found. A changed region too large to compare is marked as not compared instead of being guessed, and a very long changed line may be marked as a whole instead of word by word. The tool says so when either happens.

Is there an input size limit?

Lines that match at the start and end of both texts do not count toward the limit. The changed region between them is compared when it has at most 12,000 lines on each side and 1.5 MB in total; a larger changed region is marked as not compared. Text files up to 10 MB can be loaded. The diff runs in a Web Worker so the page stays responsive.

Can I swap the two texts?

Yes. Swap left / right in the side panel exchanges the original and updated text, so additions show as removals and the other way round.

Compare Two Texts

Paste two versions of any text and see them compared column by column with added, removed, and unchanged lines clearly marked. Useful for proofreading edits, reviewing translations, and checking config differences. All processing runs in your browser.

Original

Drop a text file or click to choose

Updated

Drop a text file or click to choose

+ 0 added− 0 removed= 0 unchanged

Original

Updated

Paste text in both panes above to see the diff.

VIEW

Try Word diff Try Git-like

ACTIONS

Runs entirely in your browser

How it works

The comparison starts in a Web Worker as soon as either text changes. The worker splits both texts into lines, sets aside the lines that match at the start and end, and runs a longest common subsequence (LCS) comparison on the region between them, within 12,000 lines per side and 1.5 MB in total. Changed lines are then paired and compared word by word, and the counts of added, removed and unchanged lines appear above the result. Swap left / right exchanges the two inputs and runs the comparison again.

Processing runs in your browser

All diffing is done locally using browser APIs. Our servers are not involved at any point.

Frequently asked questions

Can I compare any kind of text?: Yes. Paste prose, code, configuration, logs, or any other text. The diff algorithm works on lines and words, so it handles any content your browser can display.
How accurate is the comparison?: The diff uses a longest common subsequence algorithm on lines, then highlights the words that differ inside each changed line. Within the size limits every changed line is found. A changed region too large to compare is marked as not compared instead of being guessed, and a very long changed line may be marked as a whole instead of word by word. The tool says so when either happens.
Is there an input size limit?: Lines that match at the start and end of both texts do not count toward the limit. The changed region between them is compared when it has at most 12,000 lines on each side and 1.5 MB in total; a larger changed region is marked as not compared. Text files up to 10 MB can be loaded. The diff runs in a Web Worker so the page stays responsive.
Can I swap the two texts?: Yes. Swap left / right in the side panel exchanges the original and updated text, so additions show as removals and the other way round.

Related operations

For making the same change everywhere in one file, try find and replace. To put both inputs in matching order before comparing, use sort lines. For diffing two JSON payloads after pretty-printing, see the JSON formatter.

Last reviewed September 30, 2026

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