Split ChatGPT custom instructions, memory and projects
Compare the scope of ChatGPT custom instructions, memory and projects in one table, then see what to put in each, with example text and how to delete memory.
Sort what you repeat into three places so you stop retyping it. Follow the steps below.
[1] Compare the scope of the three features.
| Custom instructions | Memory | Projects | |
|---|---|---|---|
| Scope | All chats | All chats (projects depend on the setting) | Chats inside that project |
| Where to switch | Settings > Personalization · Enable customization | Settings > Personalization > Memory | Project ••• > Project settings |
| What goes in | Format, tone and basics that fit any task | Facts and preferences picked up from chats | Rules, files and background for that one job |
| Who writes it | You | Mostly ChatGPT saves it | You |
[2] Open custom instructions. Go to Settings > Personalization, confirm Enable customization is on, and type into the Custom Instructions field. The save limit is 1,500 characters on Free and Go, and 5,000 on Plus, Pro, Enterprise, Business and Education.
[3] Put only task-independent format and tone in custom instructions. This example is hand-written.
Give the conclusion first, then the reasons.Keep explanations short.Put commands and code in code blocks.If you are unsure or do not know, say so instead of guessing.When a term is not English, add the English term in parentheses once.[4] Create a project and add its instructions. Open the project's ••• menu, choose Project settings, and write rules that fit only that job. This example is hand-written.
This project polishes drafts of the weekly team report.Input is bullet notes. Output is three sections: "Done / Blocked / Next week".Use at most three bullets per section, and use only numbers and dates present in the input.If an uploaded file uses a different template, follow the template and note the difference in one line.[5] Pick the project's memory mode. A project uses either default memory or project-only memory. Choose it when you create the project; you can change it later in project settings.
- Default memory: your saved memories apply, and chats can draw on other conversations in the same project.
- Project-only memory: saved memories are not used in project chats, and chats cannot reference conversations outside the project.
[6] Review what memory holds. Open Settings > Personalization > Memory. Depending on the account you see Reference saved memories, Reference chat history, Memory summary or Manage. Turning off Reference saved memories also turns off Reference chat history.
[7] Delete what you do not want kept.
- One item: in the saved memories list, click ••• next to it and choose Delete.
- Everything: click ••• beside the search bar and choose Delete all.
- Summary-style accounts: type a correction in the box under Memory summary, or highlight text in the summary to correct it. A June 2026 note says the summary page's ••• menu has Delete and turn off memory.
- To leave no trace: start a Temporary Chat. It does not create or update memories. Choose Unpersonalized before starting to skip existing memories and custom instructions too; this cannot be changed after the chat starts.
[8] If the screen does not match, check these.
- Menu names and items vary by plan, platform and date. A June 2026 note says memory now updates automatically and the legacy list is at Settings > Memory > Saved memories; older help text says Manage memories.
- A July 15, 2026 note raised the paid-plan custom instructions limit from 1,500 to 5,000 characters. It does not state a new Free limit.
- Whether custom instructions apply inside project chats: a table in the docs (Enterprise and Edu) lists "only project instructions". Repeat any rule you need in the project instructions.