OpenAI is removing GPT-4.5 from ChatGPT on June 27, 2026, after a 30-day sunset period that began in late May. For the vast majority of users, this change will be invisible. However, creative writers who relied on the model's distinctive tone and developers who built custom workflows around it will need to make adjustments before the deadline.

Why Is OpenAI Retiring GPT-4.5 Right Now?

This retirement is part of OpenAI's regular model housekeeping. The company has been streamlining its ChatGPT lineup throughout 2026, removing older models to reduce complexity and operational costs. GPT-5.2 was pulled from the lineup on June 12, and the older o3 model is scheduled for removal on August 26. Running multiple overlapping models simultaneously is expensive and creates confusion in the model picker, so OpenAI is consolidating around its newest offerings.

The company argues that GPT-5.5, which has been the default ChatGPT model since May 5, is now superior across the board. More importantly, OpenAI spent the spring specifically tuning GPT-5.5 to write in a more natural, less robotic style, partly in response to user complaints that newer models had lost the warmth of older versions.

What Happens to Your Existing Conversations?

Your saved chats won't disappear. When OpenAI retires a model, existing conversation threads retain their full history, so you can still scroll back and read everything you've written. The only change is that new messages in those conversations will run on the current default model instead of the retired one. When GPT-5.2 was retired on June 12, OpenAI quietly migrated those conversations to GPT-5.5, and the same process will happen with GPT-4.5.

Who Actually Needs to Do Something Before June 27?

The honest answer depends on how you use ChatGPT. Here's the breakdown of who should take action:

• Default Users: If you simply open ChatGPT and type without touching the model dropdown menu, you've been on GPT-5.5 Instant since May 5 and nothing changes for you on June 27.
• Free Account Holders: Free ChatGPT accounts run exclusively on GPT-5.5 Instant, so you were never selecting GPT-4.5 in the first place.
• Creative Writers: If you specifically chose GPT-4.5 because you loved its tone and voice for writing emails, stories, or other creative work, you'll feel this change. One Pro subscriber described losing GPT-4.5 as "losing a creative partner," and that sentiment is real.
• Custom GPT Builders: If you created custom GPTs or automated workflows that explicitly call GPT-4.5, you need to check your settings before June 27 and switch them to GPT-5.5.
• Enterprise Users: Teams, Enterprise, and Education plan administrators may have access to legacy-access toggles that consumer accounts don't, so check with your workspace manager if a specific model is baked into a critical process.

How to Prepare Your Workflows Before the Deadline

If you fall into the group that needs to make changes, here are the concrete steps to take before June 27:

• Check Custom GPTs: Open any custom GPTs you've created and review the model setting. Switch it from GPT-4.5 to GPT-5.5, then run your usual prompt once to see how the output compares.
• Test Your Tone: If you built workflows around GPT-4.5's specific voice, save a "match this tone" prompt. Paste two or three paragraphs of writing you like and instruct GPT-5.5 to match that style, tone, and format. Models respond to explicit tone guidance far more effectively than most people expect.
• Update Pinned Models: If you have any pinned model selections in your ChatGPT settings, change them to GPT-5.5 now rather than waiting until after the 27th.
• Document Your Preferences: For any workflow that depends on a specific model's quirks, add a sentence or two to your instructions about the tone, format, or style you want. This makes your prompts more portable across model updates.

What GPT-5.5 Can and Cannot Do

GPT-5.5 is not simply GPT-4.5 with a new label. The tone is genuinely different, and if you had a workflow finely tuned to GPT-4.5's exact characteristics, you'll need to re-tune it. A well-written prompt can get you most of the way back to your original results, but it won't be identical.

One important limitation: you cannot get GPT-4.5 back after June 27 in the ChatGPT app. There's no hidden setting, no legacy mode button, and no way to access it through the consumer interface. For API users building applications, the situation is different. OpenAI documents that retired models stay available via the API on a separate timeline, so if your app calls GPT-4.5 through the API, that's a different track with its own deprecation schedule.

The broader issue that retiring GPT-4.5 doesn't solve is the confusing model picker itself. ChatGPT's dropdown menu still lists Instant, Medium, High, Extra High, Pro, and other options that leave many users bewildered. Removing GPT-4.5 does make the list slightly shorter, which is a small mercy, but the underlying complexity remains.

The Bottom Line for Most Users

For approximately 90 percent of ChatGPT users, June 27 will be a non-event. You're already on GPT-5.5 and you'll never notice the change. For the writers and workflow builders who genuinely preferred GPT-4.5, spend ten minutes this week checking your custom GPTs, switching any pinned models to GPT-5.5, and saving a tone-matching prompt so you stop depending on whichever model happens to be the default next month. Because as OpenAI continues to streamline its lineup, there will always be a next month.