Chatting with a PDF means asking questions and getting answers tied to that file. Look at how many documents you can load at once, whether answers stay grounded in your sources, and what the free tier caps.
NotebookLM (now Gemini Notebook) is the best free option: 100 notebooks of 50 sources each, with answers drawn only from your uploads. For research papers, SciSpace Premium ($20/mo) includes unlimited Chat with PDF. For one long contract or report, Claude Pro ($20/mo) is built for long documents.
| App | Free tier | Paid from | Top plan | Best for |
|---|---|---|---|---|
| NotebookLM (Gemini Notebook) | Yes | $4.99/mo | $99.99–199.99/mo | Students, researchers, and analysts who need grounded answers and audio summaries from their own documents |
| SciSpace | Yes | $20/mo | $200/mo | Students and researchers who want one place to find, read, analyze and write about scientific papers |
| Claude | Yes | $20/mo | $100–200/mo | Document analysis, research papers, nuanced writing, software engineering |
| ChatGPT | Yes | $8/mo | $500/mo | Everyday writing, brainstorming, image generation, casual coding |
| Monica | Yes | $9.90/mo | $99.90/mo | Users who want several frontier chat models plus summarizing, translation and writing help inside every web page for one low price |
Monthly prices in US dollars before tax, from each vendor's official pricing (US list price; weekly-billed plans converted to a monthly figure). Updated November 2, 2026
Upload your own sources and it answers only from them. Free includes 100 notebooks with 50 sources each, 50 chat queries and 3 Audio Overviews a day; with Google AI Pro that rises to 300 sources per notebook and 500 queries a day.
Pick it if: you work across many PDFs on one topic and want grounded answers.
Where it falls short: It can't be bought on its own; higher limits need a Google AI Plus, Pro or Ultra subscription.
Full NotebookLM (Gemini Notebook) pricing →A research toolkit built around papers: Premium includes unlimited Chat with PDF and literature reviews, plus Deep Research and 1,200 agent credits a month.
Pick it if: your PDFs are scientific papers.
Where it falls short: Free has only 100 agent credits a month with no rollover, and "unlimited" paid tiers run under fair-use limits.
Full SciSpace pricing →Built for document analysis and research papers, with unlimited projects on Pro to keep chats and documents organized. Free runs Sonnet 5.5 with limited daily usage.
Pick it if: you need a careful read of one long contract, report or manuscript.
Where it falls short: Usage caps are smaller than ChatGPT's, and Pro runs on a rolling 5-hour session limit.
Full Claude pricing →File uploads are included even on Free, next to unlimited text chats, so you can drop a PDF into an ordinary conversation.
Pick it if: you only occasionally need a summary or answer from a file.
Where it falls short: Output quality varies between model tiers, and it isn't built around a set of sources the way NotebookLM is.
Full ChatGPT pricing →Its ChatPDF tool sits inside a browser, desktop and mobile assistant with GPT, Claude and Gemini models. Pro ($9.90/mo) includes 1,500 Advanced Credits a month shared across ChatPDF, agent, image and video tasks.
Pick it if: you want PDF chat next to the page you're reading.
Where it falls short: Free gets only limited ChatPDF trials, and credits are shared with image and video tasks.
Full Monica pricing →For one long document, any assistant with file uploads works, and Claude Pro's projects keep it next to your chats. For dozens of sources, use a tool that holds them together: NotebookLM's free plan stores 50 sources per notebook and answers only from them, so replies stay tied to the material you uploaded.
Yes. NotebookLM's free tier holds 100 notebooks with 50 sources each and 50 chat queries a day, and ChatGPT Free includes file uploads. Monica's free plan has only limited ChatPDF trials.
NotebookLM when you want answers drawn only from your own sources across many files. ChatGPT when you want one PDF summarized inside a general chat.
How we choose: prices come from each vendor's official pricing page and are re-checked every week. We take no affiliate fees, so rankings aren't for sale.