Free Text Compare & Diff Checker

Compare two versions without uploading either one

Paste an original and revised text to see added, removed and modified lines side by side. Modified lines include inline word-level highlights, while the summary shows unchanged lines and a deterministic similarity percentage.

Everything runs in the active browser page. DraftFort does not receive or save either text, and this page deliberately has no browser-draft feature. Comparison starts only when you select Compare text, avoiding expensive work on every keystroke.

What this diff checker compares

The tool first aligns complete lines, then pairs neighboring removed and added lines as modifications. It highlights the changed words and punctuation within each paired line. Lines that exist on only one side remain clearly marked as an addition or removal.

This is useful for reviewing copy edits, contract drafts, release notes, configuration snippets, transcripts, translated text and plain-text exports. It does not understand meaning or decide which version is correct.

Choose explicit comparison rules

The default comparison is exact. Optional rules change alignment without rewriting either source:

• Ignore uppercase/lowercase treats case-only changes as equal.
• Normalize spaces trims each line and collapses consecutive whitespace.
• Ignore blank lines removes empty lines before alignment while preserving the original line numbers shown in the result.

If a formal review requires exact text, leave every option off. A result can differ from Git, Microsoft Word, an IDE or another diff product because pairing and tokenization rules are not universal.

Understand the similarity score

The percentage measures unchanged aligned characters after the selected comparison rules. It is designed to summarize the displayed diff. It is not a plagiarism score, semantic similarity score, authorship test or legal redline opinion.

A small punctuation change can affect a short text more than a long document. Review the highlighted rows rather than relying on the percentage alone.

Navigate changes and export an exact patch

Use Previous change and Next change to move through long results, or turn off Show changes only to inspect unchanged context. The unified .patch download is built locally from the exact text on both sides and uses three context lines.

The patch deliberately ignores the on-screen ignore-options: case and whitespace differences remain in the file so the export never silently rewrites source text. Only download it when you intend to keep both versions in that local file.

Continue the private text workflow

Use the Word Counter to inspect length, reading time and frequency in either version. Convert reviewed technical writing with Markdown to PDF, or extract selectable text first with PDF to Text. PDF extraction can alter reading order, and image-only scans still require OCR outside DraftFort.