How to upload a PDF to ChatGPT or Claude
In ChatGPT or Claude, click the attach button (the + or paperclip next to the message box), pick the PDF and ask your question. If the AI can't read it, the PDF is often a scan with no text layer. Run OCR on it first, or convert it to Markdown and paste the text.
With PDF Unlimited (free)
Check the PDF has real text
Open it in PDF Unlimited, press ⌘F and search for a word you can see on the page. If nothing is found, the page is an image, which is common with scans.
Make scans readable
Choose Tools > Make Searchable (OCR) and save. The scanned pages get a text layer that an AI, or anyone, can read and copy.
Send only what matters
In Pages mode, extract the pages you actually want answered into a new PDF, or use File > Export Compressed… if the file is too big to upload.
Upload it
In ChatGPT or Claude, click the + or paperclip button next to the message box, choose the PDF and type your question.
Or paste Markdown instead
For complex layouts, convert the PDF with the free PDF to Markdown converter on pdfunlimited.app, copy the result and paste it into the chat.
Why an AI misreads some PDFs
A PDF is a page layout, not a document with paragraphs. Most of the time the text inside is clean and an AI reads it fine. Trouble starts with scanned pages, which are pictures of text, with multi-column layouts that get read across instead of down, and with tables that come out as a jumble of numbers.
The quickest test is search. If ⌘F finds the words, the text is real. If it finds nothing, make the PDF searchable before you upload it.
Why Markdown often works better
Markdown keeps the structure that matters to a language model: headings stay headings, lists stay lists and tables stay rows and columns. You can also see exactly what the model will read, and fix anything odd before you send it.
PDF to Markdown converts in your browser, so the file is never uploaded to us. It reads the text layer directly and runs OCR only on the parts that are scanned.
Keep private documents private
When you upload a file to an AI chat service, it is processed on their servers under their data policies. Check those settings before you share anything sensitive.
For contracts, medical forms and bank statements, redact the personal details first. In PDF Unlimited, Redact mode removes the marked content from the page instead of covering it, so it cannot be copied back out. Save the redacted copy under a new name and upload that.
- Remove names, account numbers and addresses the AI does not need.
- Extract only the relevant pages with split.
- Keep the original, unredacted file on your Mac.
Huge PDFs and long reports
Very long PDFs can be too big to upload, or too long for the AI to give careful answers about every part. Split them into the chapters you need, or compress image-heavy files first. Asking about one section at a time usually gives sharper answers than asking about 300 pages at once.
Questions
Why can't ChatGPT read my PDF?
Usually because the pages are scanned images with no text layer, or the layout is complex. Run Tools > Make Searchable (OCR) in PDF Unlimited, or convert the PDF to Markdown and paste the text.
Can I upload a PDF to Claude?
Yes. Click the attach button next to the message box and choose the file. The same fixes apply: OCR scans first, and trim long files to the pages you need.
Should I convert a PDF to Markdown before giving it to an AI?
For simple text, uploading the PDF is fine. For tables, multi-column pages or scans, Markdown gives the model cleaner structure and lets you check what it will read.
Is it safe to upload confidential PDFs to ChatGPT?
That depends on the service's data policies and your settings. The safest habit is to redact personal details first and upload only the pages you need.
Does PDF Unlimited have AI built in?
No. PDF Unlimited never connects to the internet. It prepares PDFs (OCR, redaction, splitting, compression) so whichever AI you choose can read them well.