How to summarize a long PDF or document with AI, without missing what matters

Prep the file (30 seconds)

• Check it's real text. Try selecting a sentence in the PDF. If you can't, it's a scanned image. Some assistants can read scans, but results vary. A free fix: upload it to Google Drive and choose Open with → Google Docs, which runs text recognition, then use that text.
• Remove what shouldn't leave your computer. Account numbers, ID numbers, medical details and other people's personal data. If the document is confidential at work, check your company's AI policy first.
• Know your goal. "Decide whether to sign", "prep for a meeting" and "study for a test" need very different summaries.

Ask for a structured summary, not a paragraph

Attach the file with your assistant's upload button (usually a paperclip or +), then paste a prompt that says who you are and why you're reading.

I've attached a document. I'm [who you are] and I need to [your goal, e.g. decide whether to renew this contract / brief my team / study for an exam].
Summarize it in this format:
1. One-sentence bottom line.
2. The 5-7 most important points, each with the page or section number it comes from.
3. Numbers, dates, deadlines and costs mentioned (as a table: item | value | page).
4. Anything unusual, risky or easy to miss.
5. Questions I should ask or things I should double-check.
Only use what's in the document. If something isn't covered, say "not in the document" instead of guessing.

Verify with page references and quotes

The page numbers from Step 2 are your safety net. Spot-check the two or three points that matter most for your decision. For anything high-stakes, ask for the exact wording:

For points [2] and [4], quote the exact sentences from the document that support them, with page numbers. If you can't find a direct quote, tell me.

If a quote doesn't appear when you search the PDF (Ctrl+F or Cmd+F), treat that point as unverified.

Handle very long documents in chunks

Every assistant has a limit on how much text it can consider at once. When a document is too long, the summary often gets vague about later sections or skips them entirely. A quick test:

What does the final section of the document cover? List its headings and one key detail from each.

If the answer is fuzzy or wrong, split the work: summarize one chapter or 20-30 pages at a time, then combine.

Here are summaries of each part of a long document, in order:
[Part 1 summary]
[Part 2 summary]
[Part 3 summary]
Combine them into one summary using the same format as before. Point out any places where the parts contradict each other.

Ask targeted questions

Once the assistant has the document, use it like an expert you can quiz. These work well for leases, contracts, policies and terms of service:

Based only on the attached document:
- What am I required to do, and by when?
- What fees, penalties or automatic renewals are there?
- How can I cancel or get out of this, and what does it cost?
- What rights does the other party have that I might not expect?
Give page numbers for each answer.

An AI summary of a contract is a reading aid, not legal advice. For anything with real money or legal risk, use it to prepare questions for a professional.

Turn the summary into something you'll use

A summary is only useful if it leads somewhere. Ask for the output you actually need next:

Using the summary above, create [pick one]:
- a one-page brief for my manager, with a recommendation at the top
- a checklist of actions with deadlines
- 10 flashcards (question / answer) for studying
- a short email to [person] explaining the 3 things they need to know

For more ways to keep AI honest, see how to research with AI without getting fooled. To turn the result into a team update, see turning notes into summaries and action items.