# Compare PDFs

> Spot text differences between two PDF versions.

URL: https://uttir.com/pdf-compare
Categories: pdf-tools
Privacy: Both PDFs are compared locally in your browser and never uploaded.

## About

Compare PDFs extracts the text layer from two documents and lines them up with a word-quality diff: added lines are highlighted green, removed lines red, and long unchanged stretches are collapsed so you can jump straight to the changes. Line numbers and pages are shown for every difference.

It is a text comparison, not a pixel comparison — perfect for contracts, policies, and reports where the wording is what matters. Everything is computed in your browser; neither file is uploaded.

## How to use

1. **Choose both PDFs** — The original first, then the revised version.
2. **Run the comparison** — Differences are highlighted immediately.
3. **Review the changes** — Green lines were added, red lines were removed.

## FAQ

### Does it detect formatting or image changes?

No — it compares text content. Moved paragraphs may appear as remove+add if their wording also changed; identical reordering of identical lines is not flagged.

### Can I ignore case or whitespace?

Yes. Toggle "ignore whitespace" to hide reflow-only changes, and case sensitivity when capitalization differences do not matter.

### Are scanned PDFs supported?

Only after OCR. The comparison works on the text layer, so run both files through the OCR PDF tool first if they are scans.

### Is there a page or size limit?

Very large documents are compared with a reduced context view to keep the diff responsive. Files up to 50 MB are accepted, matching the other PDF tools.

## Related tools

- [PDF Merge](https://uttir.com/pdf-merge) — Combine multiple PDFs into one, in the order you choose.
- [Unlock PDF](https://uttir.com/pdf-unlock) — Remove the password from a protected PDF you own.
- [JSON Diff](https://uttir.com/json-diff) — Compare two JSON values semantically. Ignores key order, highlights added/removed/changed paths, and works with nested objects and arrays.

---

For the full HTML page with the live tool, visit https://uttir.com/pdf-compare.
This file is the markdown rendering at https://uttir.com/pdf-compare.md. See https://uttir.com/llms.txt for a site-wide summary.