Why long PDFs are hard for AI
Language models read a limited amount of text at once (their context window). When a document is longer, many tools cut it — keeping the beginning and dropping the rest — or ask the model to cope with a giant prompt where details in the middle get lost. The result is a summary of the introduction presented as a summary of the document.
How this tool handles it
- Page-aware extraction — the text is read page by page, keeping page numbers.
- Splitting — pages are grouped into parts of roughly 15,000 characters, without cutting a page in two when possible.
- Map — each part is analysed separately and turned into dense notes with figures, names, dates and page references. Parts are processed in parallel.
- Reduce — the notes are merged into the final summary with the length, format and language you chose.
The same document then stays available for questions: for each question, the most relevant passages from all 300 pages are selected and used to answer.
How to summarize a long PDF
- Upload the PDFUp to 300 pages. Comprehensive length is preselected on this page.
- Watch the progressThe parts are read in parallel; you'll see “part 7/18”.
- Read the merged summaryOrganised with headings, with page references.
- Drill downAsk about a chapter, a section or a specific term.
Over 300 pages?
Split the document into parts of up to 300 pages (any free PDF splitter does this), summarize each part, then ask for key points of each one. For scanned PDFs, OCR covers the first 40 pages on the free tool.
Frequently asked questions
How long does a 300-page PDF take?
Usually 20-60 seconds depending on text density and load. You see progress as each part is read.
Is any part of the document skipped?
No. Every part is analysed. In the rare case of an extremely dense document beyond the processing limit, the summary states that only the first parts were analysed.
Can I ask questions about page 250?
Yes. Questions search the whole document and the answer cites the page.
Which length should I choose?
Comprehensive (about 800 words with headings) for books and reports; Detailed if you only need the main line.