How do I summarise a long PDF without uploading the file?

A forty-page report lands in your inbox with a note saying "can you look at this by Friday". Before you read it, you want two minutes of knowing what it is, so you can decide how much of Friday it needs.

A summary does that. But not everyone is happy to "upload a document to an AI", least of all a contract, so here is how the summary gets made.

What happens to your file

People mean two different things by "uploading a PDF".

The file. The PDF itself, with its images, signatures, attached files and everything else. Summarize PDF never sends this anywhere. Your browser opens it and reads the words out of it on your own machine, the same way it would if you opened it in a PDF reader.

The text. The words your browser found. To write the summary, that text is sent to an AI service, which writes the summary and sends it back. Only the first 60,000 characters are sent (roughly 10,000 words of English), so on a very long document the written summary covers its opening part. We do not store the text or the summary.

In short, the document stays on your device and its words are used once to write the summary. The tool says this on the page before you choose a file, so you know before you start.

What you get back

There is one kind of summary, with no choice of length. It starts with a line naming what the document is, then gives between six and fourteen short facts, each a label and a value: who it concerns, the amounts, the dates, the terms, and anything that asks somebody to do something.

You can read it in a few seconds, and it sits beside the document itself, so you can check any figure in it against the page it came from. Use it to decide whether to read the document, or to know what you would be missing if you do not.

Can you trust the numbers?

The AI is told to use only what the document says and to copy any figure exactly as it is written instead of working one out. In testing on a real invoice, the totals, dates and bank details came back character for character.

So you can trust a summary to help you decide what to read. Don't sign something you have only seen summarised, though. A summary is made to be read quickly, and a contract needs to be read slowly.

When it will not work

Scanned documents. A scan is a picture of words, so there is no text for your browser to read and nothing to summarise. The tool tells you so instead of producing an empty summary. Run the file through OCR PDF first to turn the picture back into text, then summarise the result.

The quick test: try to select a line of text in your PDF reader. If it highlights, there is text. If the whole page selects as one block, it is a scan.

Forms, receipts and tables. These are mostly labels and numbers with very little prose. You will get an accurate description of what the document is, but there is not much to condense.

If the AI summary is not available

Everyone gets three AI-written summaries in any 24 hours, and signing in does not raise that. Once they are used, you still get something. Your browser has already read the document and shows the key facts it found: what kind of document it is, its length, labelled details such as names, dates and amounts, its sections and its main sentences. You see that instead of the written summary.

The same happens if the AI service is briefly down. You still get the facts your browser found, and nothing about your file changes.

Other languages

The summary is written in the language the document is written in. A Bangla report gets a Bangla summary, and a document mixing Bangla and English is handled as it is.