Compare PDF Text on Android — Line by Line

How to compare two PDFs

Pick the old file and the new file

Compare text takes two files with separate slots. If you picked them the wrong way round, one tap swaps them. Encrypted files ask for their password first, like anywhere else in the app.

Read the counts

The report opens with real line counts: all, added, deleted and modified. They are counted lines, not a score, so you can tell a one-line fix from a rewritten section at a glance.

Filter and step through

Filter the differences by type and jump from one to the next with previous and next. Inside a modified line, the diff drops to word level, and the affected characters are boxed so you can see exactly what changed.

Switch between old and new

Toggle between the old view and the new view to read either side of each change in place, then decide what the difference means.

What the comparison sees

Text is extracted on the phone and aligned line by line across pages. Because alignment is by content rather than by page position, an inserted page does not shift every difference after it — the matching lines are found again on the far side of the insertion.

Within a line that changed, the comparison drops from line level to word level: the unchanged words around the edit stay quiet, and the words that differ are marked character by character. A one-word amendment in a long clause is visible as exactly that.

What it ignores and what it refuses

Compare text reads the text layer, not the pixels. Three things are deliberately out of scope:

Images — a file where only a picture changed shows no text differences.
Formatting-only changes — a different font, margin or color is not a text change.
Paragraphs that merely moved — identical lines exist in both files, so the move is not reported as a difference.

The consequence is stated plainly: two files that look different but read the same may show no differences. When the words are what matter — contracts, policies, specifications — that is the comparison you want, and it is why the counts can be trusted.

A file with no extractable text has nothing to compare: the tool says so and points to OCR first. OCR on Android adds the missing text layer on the device, after which the comparison runs normally.

There is also a size the tool will not pretend to handle. Past 10,000 lines or the eight-million-cell alignment budget, the comparison refuses with an explanation instead of returning a truncated report — a partial comparison that looks complete is worse than none.

Where comparison ends, replacement begins: find and replace PDF text on Android rewrites wording across a whole document and reviews every match with you. PDFMason is on Google Play — the download page has the store link. Everything is free during early access, and a one-time purchase is planned for the future.

FAQ

Does the comparison include images or formatting?

No. It reads the text layer only: images, formatting-only changes and paragraphs that merely moved are out of scope. Two files that look different but read the same may show no differences.

What if one of my PDFs has no text layer?

The tool reports that there is no extractable text and sends you to OCR first. The OCR model is bundled in the app and runs on the phone, so the scanned file gains a text layer without leaving the device.

Is there a size limit for comparing documents?

Yes, and it is enforced rather than fudged. Past 10,000 lines or the eight-million-cell alignment budget, the comparison refuses with an explanation instead of returning a truncated result.

Can it compare password-protected PDFs?

Yes, after the password: enter it once and the file opens like any other. The comparison itself then runs entirely on the device.

What counts as a modified line?

A line the alignment matched across both files whose words nevertheless differ. The word-level diff inside it shows exactly which words changed, with the affected characters boxed.

Does inserting a page ruin the comparison?

No. Lines are aligned across pages by content, so an inserted page does not shift every later difference — the matching lines are found again after the insertion.

PDFMason for Android is coming

The browser tools handle whole pages. The app edits the text inside them — on your device, with nothing uploaded.

Edit the text and images already in the PDF
Convert to Word, Excel and PowerPoint — no upload
OCR, redact, fill and sign — everything on the phone

Scan to install Opens Google Play on your phone