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AI assistants now remember things about you by default. ChatGPT, Gemini and Copilot can all carry details from one chat into the next. That makes them more useful. It also means a passing comment about your health, your boss or your money can follow you around for months.

The good news is that all three let you see and erase what they keep. The bad news is that the controls are split across several settings, and the names don't match from one app to the next. Deleting a chat is not the same as deleting a memory. Turning off training is not the same as turning off memory. Here is how each one works and what I'd do about it.

What memory means in 2026

Four different things get lumped together as memory. It helps to keep them apart.

Memory is what the assistant uses about you to shape future answers. That can be a fact you asked it to keep, like your job or your diet. It can also be something it picked up from past chats on its own.

Chat history is the list of your past conversations. It is a record, like your email inbox. The assistant may or may not draw on it, depending on your memory settings.

A temporary chat is a one-off conversation that does not land in your history and does not feed memory. It is the closest thing to an incognito tab.

The training setting decides whether the company can use your chats to improve its AI models. It has nothing to do with what the assistant remembers about you. You can turn training off and keep memory on, or the other way around.

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ChatGPT

OpenAI says ChatGPT's memory can draw on saved memories, past chats, custom instructions, files in your Library and connected apps such as Gmail, depending on your plan and region. You find the controls under Settings, then Personalization, then Memory.

There are two main switches. Reference saved memories covers the facts ChatGPT has stored about you. Reference chat history lets it pull from past conversations. OpenAI says turning off chat history means information remembered from past chats is scheduled for deletion within 30 days. Your chats themselves stay in your history unless you delete them.

Newer accounts also get a memory summary. It is a short overview of what ChatGPT thinks it knows about you. You can correct it, pick Don't mention this again or choose Delete and turn off memory. OpenAI is clear that the summary does not list everything. You can also simply ask ChatGPT what it remembers about you.

Temporary chats in ChatGPT do not create or update memories. OpenAI says you can choose before you start whether a temporary chat uses your existing memories at all, with an option called Unpersonalized. If you save a temporary chat, it becomes a regular chat and follows your normal settings.

Training is a separate switch called Improve the model for everyone, under Data controls. OpenAI says turning it off does not delete your chats. Business, Enterprise and Edu workspaces are not used for training by default. ChatGPT is also rolling out a Privacy Center that explains each control and links to it.

Gemini

Google ties Gemini's memory to a setting called Keep Activity. When it is on, your chats are saved in Gemini Apps Activity in your Google Account. Google says it is on by default for users 18 and over.

Memory of past chats sits under Settings and help, then Personal Intelligence, then Memory. Google says it needs a personal Google Account, an age of 18 or over and Keep Activity switched on. It does not work with work or school accounts.

Here is the catch. Gemini does not keep a separate list of memories you can delete one by one. Google says the way to make Gemini forget something is to delete every chat that contains it from Gemini Apps Activity. There may be a short delay before it stops using that information. You can correct Gemini in a chat, and you can ask it whether it used anything from past chats.

Keep Activity also covers training. Google says that when it is on, it uses your activity to improve its services, including training AI models, with help from human reviewers. Chats reviewed by people are disconnected from your account and kept for up to three years, even if you later delete your activity. By default, activity is auto-deleted after 18 months. You can change that to 3 or 36 months.

If you turn Keep Activity off, Google says future chats are still kept with your account for 72 hours to run the service and keep it safe. They don't appear in your activity and are not used for training unless you send feedback.

Gemini has temporary chats too, started from the button next to New chat. Google says they don't appear in your activity, are not used for personalization or training and are kept for 72 hours. 9to5Google reported the same limits when the feature rolled out.

Copilot

Microsoft's consumer Copilot app was updated in August 2026, and its privacy controls now live under Settings, then Personalization. These apply when you sign in with a personal Microsoft account, not a work or school one.

Copilot can remember details like your communication style, favourite topics and goals, according to Microsoft. Under Personalization, select Manage next to Saved memories. You can delete single memories or pick Delete all memories. Microsoft says switching Saved memories off does not delete what is already saved, so do both if you want a clean slate.

Copilot also has a One shared experience switch. Microsoft says it lets your Copilot chats personalize Bing, Edge and MSN, and lets those services shape Copilot. Personalized ads are a separate toggle, and Microsoft says personalized ads can use your chat history and saved memories.

Chat history is managed separately. You can delete a single chat from the chat list. To wipe all of it, Microsoft points you to the Microsoft privacy dashboard.

For training, Microsoft says, and The Verge has reported, that signed-in users can opt out through Training on conversation activity and Training on voice conversations in Copilot's privacy settings. Opting out covers future chats only. Microsoft says it does not train on users under 18 or on people who are not signed in. Microsoft does not list a temporary chat mode among Copilot's privacy controls.

Deleting a chat vs deleting a memory

This is where most people get caught out. In ChatGPT, OpenAI says deleting a chat does not necessarily delete a saved memory created from it. Deleting a saved memory also doesn't remove the original chat. To fully remove something, you need to delete both, plus any file or connected app that holds it. OpenAI says it may keep logs of deleted saved memories for up to 30 days.

In Copilot, memories and chat history are also separate. Delete the memory in Personalization and the chat in your chat list.

Gemini works the other way. Its memory comes from your saved chats, so deleting the chats is how you delete the memory. Turning memory off stops future use but does not erase your activity.

My advice is simple. If something sensitive slipped out, delete it in both places, and then check the memory view again a day later.

Which setting does what

If you want the assistant to stop knowing a fact, use memory controls. In ChatGPT and Copilot, delete the memory. In Gemini, delete the chats that contain it.

If you want a clean list of past chats, use chat history controls. That tidies the record but may not erase memory in ChatGPT or Copilot.

If you want one private conversation, use a temporary chat in ChatGPT or Gemini. It still gets stored for a short time for safety, but it won't shape future answers.

If you don't want your chats used to build future models, use the training setting. In ChatGPT that is Improve the model for everyone. In Gemini it is Keep Activity. In Copilot it is Training on conversation activity.

A five-minute privacy routine

Here is what I'd do once a month. It takes about five minutes per app.

First, ask each assistant what it remembers about you. Read the answer like a stranger would. Anything you wouldn't want on a sticky note at work should go.

Second, open the memory view. That means the memory summary or saved memories in ChatGPT, Saved memories in Copilot, and Gemini Apps Activity for Gemini. Delete what's wrong or too personal.

Third, decide on training. If you're not comfortable with your chats helping improve the models, switch it off once and forget about it. In Gemini, remember that this also turns off saved history and memory.

Fourth, check the auto-delete period in Gemini, and clear old chats in ChatGPT and Copilot that you don't need.

Finally, build one habit. Before you paste in a medical result, a contract or anything about another person, open a temporary chat in ChatGPT or Gemini. In Copilot, delete the chat when you're done. Memory makes these tools feel personal. A few minutes of upkeep keeps them from getting too personal.