What you get for free
Upload two PDFs of up to 30 pages each and the comparison runs immediately, with no account and no email address. The result is the same as on paid plans: a change list with page numbers, a redlined PDF you can download, and a side-by-side view with synced scrolling. The free tier is limited by page count and a daily cap, not by features. There is no watermark and no blurred preview asking you to upgrade.
A free account raises the page limit to 100 pages per document and gives five comparisons a month. That covers most individual use: a lease, a contract draft, a returned form, a revised policy from your insurer.
How to run a comparison
Open the comparison tool on the homepage. Drop the older PDF in the left box and the newer one in the right box, or click each box to browse. Pick Side by side if you want to see both documents with highlights, or Redline PDF if you want the new document marked up. Click Compare documents.
Most comparisons come back in a few seconds. Longer documents take a little longer. If you want to see what the output looks like before uploading anything of your own, use the Try with sample contracts button, which runs two versions of a short agreement.
What free online comparison tools usually get wrong
It is worth knowing the common failure modes, because they decide whether a free tool saves you time or costs you more of it.
- Comparing page by page, so one inserted sentence lights up every later page.
- Reporting page numbers and running headers on every page as changes.
- Producing a screenshot with highlights but no list, so you still read the whole document.
- Storing your upload, sometimes indefinitely. Read the privacy policy of any tool you send a contract to.
The first two are why some tools report forty changes for a one-word edit. The engine here aligns paragraphs between the two documents before comparing them, and recognises headers, footers and page numbers that repeat on every page and leaves them out. A one-word edit shows up as one change.
A quick example
Say version 1 of a services agreement says payment is due "within thirty (30) days of the invoice date", and version 2 says "within forty-five (45) days of invoice approval". That is one sentence, but two separate changes that both matter: the number of days and the date the clock starts from.
A good comparison shows both, in the same entry, with the old wording struck through and the new wording beside it, and tells you it is on page 3 of both documents. A poor one either misses "approval" because the line looks similar, or reports the whole of page 3 onwards as changed because the longer sentence pushed the text down.
How this one handles your files
Both PDFs are processed in memory for the length of the request and discarded when the response is sent. Nothing is written to permanent storage, there is no document library, and there is no "recent comparisons" list because nothing is kept. The privacy policy describes exactly what is and is not stored.
The comparison itself is rules-based, not an AI model. The same two files always give the same result, and nothing you upload is used to train anything.
If you are comparing something confidential, such as an employment contract or a loan agreement, those two points are the ones to check on any free tool. Ask where the file goes, how long it stays there, and who can see it.
The limits of the free tier
Without an account: 30 pages per document and a daily cap per network. Each file can be up to 20 MB, and the pair up to 25 MB. With a free account: 100 pages per document, five comparisons a month.
The tool needs PDFs that contain text. Most PDFs exported from Word, Google Docs or any other program do. A scan with no text layer is refused, because there are no words to compare. If you have scans, see comparing scanned PDF documents.
Word, Excel and Pages files are not accepted directly. Export both versions as PDF first and compare those.
When free is not enough
Teams that compare documents every week want volume, larger documents and an API. The Business plan is $29 for 30 days, with 500 comparisons on documents up to 100 pages, and it does not renew on its own. Enterprise covers API keys, documents up to 300 pages and private deployment inside your own network. The engine is the same on every tier. Pricing has the details.
If you are choosing between tools, what to look for in PDF comparison software lists the tests worth running on your own documents before you decide.
Try it on your own documents. Upload two versions on the homepage. Documents up to 30 pages need no account, and nothing is stored.