Short answer: a ChatGPT Project holds 5 files on Free, 25 on Go and Plus, and 40 on Edu, Pro, Business and Enterprise. A custom GPT holds 20 knowledge files. Every file still has to fit the normal limits, 512 MB and 2 million tokens for documents, and all of it counts toward a 25 GB per-user storage cap. The catch most people miss: images inside Project files may not be read, even though the same PDF works when attached to a chat.
ChatGPT Project and GPT limits (October 2026)
From OpenAI's "Uploading files and audio to ChatGPT" help article, updated 23 October 2026:
| Limit | Free | Go and Plus | Edu, Pro, Business, Enterprise |
|---|---|---|---|
| Files per Project | 5 | 25 | 40 |
| Files per GPT (knowledge) | 20 | 20 | 20 |
| Upload rate | 3 per day | 80 every 3 hours | 80 every 3 hours |
And the per-file and storage limits that apply on every plan:
| Limit | Value |
|---|---|
| Documents and presentations | 512 MB per file |
| Text and document files | 2 million tokens per file |
| Spreadsheets and CSV | About 50 MB, depending on row size |
| Images | 20 MB per image |
| Storage | 25 GB per user, 100 GB per organization |
OpenAI says it may lower the upload rate during peak hours, and it doesn't show how much of the rolling quota you have left.
Why images go missing in Projects
This is the limit that isn't a number. OpenAI's help centre says ChatGPT can analyze both text and images in PDFs, including charts and diagrams, when you attach the PDF to a chat. But "files saved as GPT knowledge or project files are handled differently from direct chat attachments. Embedded images may not be included automatically."
In practice that means a scanned PDF, which is nothing but images, can seem empty inside a Project. A report whose key figures are charts can lose them. The text of the same file still works.
The fix: attach the PDF directly to the conversation when you need its images, even inside a Project chat. For one chart or one scanned page, upload it separately as a PNG, JPEG or non-animated GIF.
When you hit a limit
- The Project is full. Remove files it no longer needs, or merge several small related documents into one PDF so they use a single slot.
- "Upload limit reached". That's the rate cap or the storage cap. If the message shows a retry time, wait until then. Otherwise check Settings, then Storage.
- Storage is full. Deleting a chat doesn't delete a file saved in Library; delete the file in Library itself. Files in GPT knowledge are removed in the GPT builder.
- A file is over the size or token limit. Split it into sections. A truncated upload is worse than a refused one, because answers look complete.
- A .gdoc won't upload. Export it from Google Docs as PDF or DOCX first.
A different model: questions across documents without a file cap
Projects work by copying files into ChatGPT. If your documents already live somewhere, a wiki, Google Drive, SharePoint or PDFs in your browser, copying them in is the step that runs into every limit above.
Sidenote reads documents where they are, in your browser and read-only, and groups the ones you're working with into a Collection you can ask across. Every answer cites the exact sentence it came from, and clicking the citation opens that passage. Collections are on paid plans and have their own plan limits, so this isn't unlimited either. The difference is that nothing is copied into a chat, so there are no Project slots, missing images or stale copies to manage.
ChatGPT Projects vs reading documents in place
| ChatGPT Projects | In-browser reader (Sidenote) | |
|---|---|---|
| How documents get in | Uploaded copies | Read where they live |
| File cap | 5, 25 or 40 per Project | Plan limits per Collection |
| Images in PDFs | May be skipped in Project files | Scans OCR'd on paid plans |
| Stays current | Re-upload after edits | Reads the live page |
| Verify an answer | Check the file by hand | Click to the exact sentence |
| Best for | Ongoing work with ChatGPT's tools | Questioning a set of real documents |
For the rest of ChatGPT's file rules, see why ChatGPT can't read my PDF. The equivalent limits for Google's tool are in Gemini Notebook limits.