What is the Summarise PDF tool?
This tool reads a PDF, scores every sentence in it, and shows you the highest-scoring ones. That is how you summarize PDF online free here: not by asking a chatbot to paraphrase your document, but by measuring which sentences carry the most distinctive information and pulling those out verbatim, with the page number each one came from.
The scoring is ordinary statistics done well. Words are weighted by TF-IDF, so terms that are frequent in this document but rare across it count for more, and common filler counts for nothing. Lines set in larger type are treated as headings, and their vocabulary tells the tool what the document is about. Sentences near the opening and the conclusion get a nudge, captions and page furniture get pushed down, and a redundancy filter stops three sentences that say the same thing from all making the cut. Search mode uses BM25, the ranking function behind most real search engines, over the same sentences.
Being extractive rather than generative is the point, not a compromise. Nothing is invented, no wording is smoothed over, every line is traceable to a page, and there is no API key, no account and no upload — a three-hundred-page report is analysed in your own tab in a few seconds. The trade-off is honest too: the output reads like a set of well-chosen quotations, not a flowing paragraph a person wrote. That makes it excellent for triage and rough drafting, and the wrong tool if you want prose to hand in as your own.
How to summarise a document online
- Drop a PDF on the upload area. Every page is read and split into sentences, and the analysis runs straight away.
- Leave the mode on Summarise and drag Summary length to the share of sentences you want — anywhere from 2% for a skim to 40% for a thorough digest.
- Look at the Key terms chips underneath. Clicking one adds it to Focus on these words, which pulls the summary towards that topic.
- Open Highlight & analysis options to change the highlight style and colour, tighten the repetition filter, order the summary by importance instead of page order, or guarantee at least one sentence per page.
- Copy the summary, save it as .txt or .md with page references, or press Download highlighted PDF to get your original marked up.
- Switch to Search to ask a question instead: matching passages are ranked and listed, and clicking one jumps the preview to its page.
Key features
- Adjustable summary length — one slider moves from a two-line overview to a detailed précis, and the counter tells you the word count, the share of the document and an estimated reading time.
- Keyword extraction — twelve key terms, including repeated two-word phrases, are pulled from the document and offered as clickable chips.
- Topic focus — type words such as revenue, deadline, warranty and sentences containing them are weighted up, which turns a general summary into a targeted one.
- BM25 passage search — ask in plain words and get up to twenty-five ranked passages, each with its page number, rather than a literal string match.
- Highlighted PDF export — the chosen sentences are marked on a copy of your file as a fill, an underline or an outline box, in any colour and strength you like.
- Optional summary cover page — insert the summary itself, with key terms and page references, at the front of the exported PDF.
- Redundancy and noise control — a repetition slider suppresses near-duplicate sentences, and a minimum text size setting ignores footnotes and small print.
- Three ways to save — plain text and Markdown summaries, both tagged with page numbers, plus the annotated PDF.
Benefits of using this PDF summary generator
- Instant and private. There is no upload, no queue and no API key, so a confidential board pack or an unpublished paper can be triaged without leaving your machine.
- Every line is verifiable. Sentences are quoted exactly and tagged with their page, so you can check the source in one click instead of trusting a paraphrase.
- Nothing is fabricated. Because the tool selects rather than writes, it cannot invent a figure, a date or a conclusion that is not in your document.
- It scales to long files. Analysis is local and linear, so a long report costs you a few seconds and no per-page fee.
- Reusable output. The highlighted PDF makes a good reading copy for a meeting, and the Markdown export drops straight into your notes.
Who should use this tool?
Students revising
Set the length low, read the twenty sentences that come out, then raise it when a topic looks important. The highlighted PDF is the useful artefact here: it gives you a marked-up copy to reread the night before an exam, with the page references intact for your notes.
Researchers triaging papers
Deciding whether a paper is relevant should take two minutes, not twenty. Skim the top sentences, glance at the key terms to see what the paper is really about, then use Search to ask about the method or the dataset before committing to a full read.
Managers scanning long reports
A ninety-page consultant report before a meeting is a familiar problem. Focus on the words that matter to you — cost, timeline, risk — order the summary by importance, and add the summary page at the front of the PDF you take into the room.
Legal, procurement and compliance readers
When you need to know what a contract says about liability or termination, Search beats reading. Type the concept, work down the ranked passages, and highlight the clauses you want a colleague to look at before sending the file on.
Frequently asked questions
Does this use AI like ChatGPT?
No, and that is deliberate. It is an extractive summariser: sentence scoring with TF-IDF, heading weighting, position bias and a redundancy filter, all computed in your browser. It never rephrases or generates text, so it needs no API key and cannot hallucinate — but the result reads as selected sentences rather than fluent new prose.
Is the PDF summary generator free?
Yes. No signup, no credits and no page limit, because there is no model to pay for — the analysis runs on your own processor.
How long will the summary be?
You decide. The slider selects a percentage of the document's sentences, from 2% to 40%, and the line under the summary box shows exactly how many sentences and words that came to, plus a rough reading time.
Can I get key points about one specific topic?
Type the terms into Focus on these words, or click any of the extracted key terms. Sentences containing those words are weighted up strongly, which is the quickest way to turn a general overview into an answer about payment terms, safety or whatever you care about.
Why does my PDF give an empty summary?
Almost certainly because it is a scan with no real text in it, and the tool says so when it sees that. Run it through OCR to recognise the characters first, then summarise the searchable version.
What is the difference between Summarise and Search?
Summarise picks the most informative sentences in the whole document. Search ranks sentences against a question you type using BM25 and lists the best twenty-five, so it answers a specific query instead of giving you an overview. Both use the same highlighting and export.
How can I save the summary?
Copy it to the clipboard, download a .txt or a .md file with page references, or export the annotated PDF with an optional summary page at the front. One caveat: that inserted page uses a standard Latin font, so non-Latin scripts come out as question marks there — use the .txt or .md export for those.
Does it change my original document?
No. Highlights are drawn onto a copy that your browser downloads as a new file, and the marks are exactly the ones shown in the preview. Your source PDF on disk is untouched.
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