How to chat with multiple PDFs at once (and compare them)

Most questions about documents are really questions about several documents. Which of these three offers has the longest notice period? Which report mentions the new supplier? Do the two studies measure the same thing? Asking each PDF one at a time works, but it means opening each chat, repeating the question and comparing the answers yourself.

Multi-PDF chat does the repeating for you, so you can chat with multiple PDFs at once. You put related PDFs in one folder of your library, open the folder, choose "Ask all PDFs in this folder", and ask one question. askPDF looks through the documents in that folder and answers with citations that name both the document and the page.

This guide explains how it works, what it is good at, and where it is not the right tool. Multi-PDF chat is available on the Plus and Pro plans.

What Multi-PDF chat does

Your library already lets you organise PDFs into folders. When a folder is open you will see an "Ask all PDFs in this folder" button. It opens a conversation that is tied to the folder, with the folder's documents listed beside it, each with its status.

When you ask a question, askPDF looks through the ready documents in the folder for the passages most relevant to your question. It searches every ready document, then keeps the most relevant passages overall, with a cap per document so one long file cannot crowd out the others. A document whose best passage is nearly as relevant as the top one always gets a place. The answer is then written from those passages.

Answers carry chips that name the file and the page, for example "Offer B.pdf p. 4". Click it and that document opens beside the chat at that page, so you can read the source yourself.

Good questions for a folder

Multi-PDF chat works best when the question is about a topic and you want to see how each document treats it. Some examples:

• "Compare what each document says about payment terms."
• "Which of these files discuss renewal?"
• "How do the three reports describe the main risks?"
• "How does each paper collect its data?"
• "What does each lease say about the deposit?"

Notice the pattern. Each question names a topic, and the answer is a comparison or a pointer to the right file. That is the sweet spot: finding which document says what, and putting the answers side by side.

What it does not do

It is worth being clear about the limits, so you do not trust it for the wrong job.

Multi-PDF chat reads the most relevant passages across the folder, not every page of every file. That means it is not a good way to ask for a complete list ("list every date in these contracts") or a full summary of a whole document. For a whole-document overview, open that single document and read around its cited pages. For a complete audit, you still need to read the source.

It also answers only from the documents in the folder. If the folder does not contain the information, the right answer is that it is not there, and you should check the cited pages when an answer sounds surprising.

Finally, only documents that are ready are searched, and at most 30 of the folder's most recently updated ones. The page tells you when some are still processing or when the folder holds more files than it can search at once. If that matters for your question, move the key files into a smaller folder.

A simple way to work

1. Make a folder for one project. Keep it focused: the offers you are choosing between, the papers for one review, the contracts for one client.
2. Wait for the files to be ready. Statuses are shown beside each document.
3. Start with a broad topic question. "How does each document handle termination?"
4. Click the chips. Open the cited page for anything you plan to rely on.
5. Follow up in single-document chats. Once you know which file matters, open it on its own and ask more detailed questions about it.

This two-step rhythm, the folder first and a single document second, is usually the fastest way to go from a pile of PDFs to a decision.

How it counts against your plan

A Multi-PDF chat question costs the same as a normal question. It uses one of your daily questions or one credit, depending on which answer model you choose in the menu, exactly as a question about a single PDF does. There is no extra charge for the number of documents in the folder.

Try it

If you want to see how it feels, read the guide to chatting with multiple PDFs, or browse the other use cases to find the kind of document you work with. And if you only have one PDF to start with, the guide on how to chat with a PDF covers the basics, from upload to checking the page.

Whatever you ask, keep the habit that makes any AI answer trustworthy: click the page, read the passage, and decide for yourself.