Drop the old file and the new one above. Every page is compared, and you are told which pages differ and where — then you can look at any of them four ways: swipe, overlay, blink, or a difference view that boxes what moved.
Nothing is uploaded. Both files are read and compared inside your browser.
Every other PDF comparison is a text diff
Worth knowing before you try three of them.
The well-known tools — Adobe's, Draftable, Diffchecker, the ones in the big PDF suites — compare words. They pull the text out of both documents, line it up, and colour what was inserted and deleted. For a contract that is exactly right.
For artwork it answers a question nobody asked. A designer's change is a logo that moved four millimetres, a photo swapped for a nearly identical one, a price set in a slightly different weight, a bleed that grew. None of that is a text change, and a text diff reports it as nothing at all — or, worse, reports a paragraph as "moved" because the layout reflowed around something you cannot see.
This page compares what the pages draw. It rasterises both documents and looks at the pixels, which is the same thing your eye would do if you had all day.
What it tells you
- Which pages differ. One line per page, so a twelve-page menu with one changed price does not need twelve comparisons.
- How much, and in how many places. "2.4% of the page changed in 4 areas" — the count matters more than the percentage, because two edits in two corners is a different job from one big one.
- Where. The difference view boxes each changed area on the newer page.
- Which page changed most, so you know where to start.
- Pages that are only in one of the two files, named rather than quietly skipped.
How to compare two PDF documents
- Drop the earlier file into Before and the newer one into After.
- Wait while the pages are compared — it runs in your browser, so a long document takes a moment.
- Read the summary, then click any page in the list.
- Switch between the four views to see the change the way that suits it.
- Press Mark up page N to open the newer file with the change already pinned, and add whatever you need to say about it.
The four views, and what each is for
- Difference — the changed areas, tinted and boxed on the newer page. The one that answers "what moved" without you looking for it.
- Swipe — drag a line across the page with the old version on one side and the new one on the other. This is what somebody actually does with a proof.
- Overlay — one version through the other, with a blend slider. Good for alignment: a logo two millimetres out shows as a ghost.
- Blink — the two versions take turns in the same frame. Astronomers found planets this way, flicking between two photographic plates, because the eye is far better at catching motion than at comparing two pictures side by side. A shift nobody spots in a split view is unmissable when it jumps.
Finding it is half of it — say what is wrong on the page
A comparison tells you page 4 changed. What you usually need next is to tell somebody, and every other tool on this search leaves you there with two documents open and a screenshot to take.
Mark up page N opens the newer file in the annotation editor, on the page you were looking at, with an orange pin already on the biggest change and the same words the page list used written on it. Draw on it, add notes, and take a PNG or a PDF away.
The pin marks the busiest change on that page — one mark, not one per area — so check the number in the list before you decide you have seen everything. The file does not go anywhere to get there: the editor is on the same page, and the bytes never left your browser in the first place.
Comparing two images
The same page does it. Drop two PNGs, JPEGs or WebPs instead of two PDFs — a picture is treated as a one-page document, and everything above works the same way. Comparing a document against a screenshot of it also works, though if the two are different shapes see below.
When two pages are a different shape
If the pages are not the same proportions — an A4 against an A3, or a portrait page against a landscape one — the difference view refuses to measure rather than reporting that everything changed. Everything did change, in the sense that no two pixels line up, and a percentage there would be a number that looks like information and is not.
The other three views still work, and the shape change itself is the finding: you can see it immediately in the swipe.
What this does not compare
It compares what the pages draw, at the resolution it drew them. It does not compare:
- text, as text — a substituted font that happens to render identically is not reported, and one that renders differently is reported as a picture change rather than as a word;
- colour profiles or separations — two files that print differently can draw the same on screen;
- metadata, links, form fields, attachments or layers;
- anything on a page it could not read, which is reported as unread and never as unchanged.
And it never tells you two files are identical. It tells you nothing changed in what these pages draw, which is a smaller claim and a true one.
When the file is not really the question
Finding the change is the easy part. What costs money is the round after it: a proof emailed to a customer, three comments in a reply, a revision, and somebody approving a version nobody meant. That is what Proofavo is for — a proof link your customer opens without an account, comments pinned to the artwork itself, and this same comparison built into the version history, so the change between round two and round three is one click rather than two downloads.
The tools that pair with this one: the PDF DPI checker for the page with the image that will print soft, crop a PDF in real millimetres, and annotate a PDF to mark up what you found here.