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Text Difference Checker
Compare two blocks of text line by line and see exactly what was added or removed.
About this tool
Whether you are comparing two versions of a contract, checking what changed in a configuration file, or reviewing an editor's revisions, spotting differences by eye is slow and error-prone. This tool compares two texts line by line using the longest-common-subsequence (LCS) algorithm, the same idea behind professional diff utilities, and highlights removed lines in red and added lines in green.
You can ignore differences in letter case or in leading and trailing whitespace, and optionally hide unchanged lines so only the changes remain. A summary shows how many lines were added, removed and left unchanged.
The comparison runs entirely in your browser, so confidential drafts, source code and legal documents are never uploaded. Inputs of up to roughly 3,000 lines each are supported.
How to use it
- Paste the original text on the left and the changed text on the right.
- Choose options such as ignore case or ignore whitespace.
- Press Compare and review the highlighted result.
Frequently asked questions
Does it compare words or characters?
It compares whole lines. For prose, put each sentence on its own line first for finer results.
Is there a size limit?
Very large inputs may be rejected to keep your browser responsive; split the files and compare in sections.
Is my text stored?
No. The comparison happens locally in your browser.
Results are provided for general information. Please read our disclaimer.