OpenAI's GPT-4.5 is here. How to try it now.
OpenAI's GPT-4.5 has arrived.
On Thursday, the ChatGPT maker announced the latest version of its LLM (large language model) in research preview. As OpenAI CEO Sam Altman said a few weeks ago, GPT-4.5 is OpenAI's last non-chain-of-thought model, meaning all future models will have reasoning capabilities.
"Early testing shows that interacting with GPT-4.5 feels more natural," said the white paper. "Its broader knowledge base, stronger alignment with user intent, and improved emotional intelligence make it well-suited for tasks like writing, programming, and solving practical problems - with fewer hallucinations."
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In the demo, OpenAI team members talked about how GPT-4.5 is not a reasoning model, but it still has advanced knowledge and can be used to reason through problems, even though it's meant to be used as general purpose tool compared to the o series which is best for science and mathematics.
GPT-4.5 is the newest addition to its GPT series since OpenAI announced GPT-4o last May. OpenAI has also shipped versions of reasoning models, o1, o3-mini, and o3-mini-high in the past year in a reported effort to focus more on models that rely on increased computing power (test-time compute) in real-time instead of extensive training and more data.
The release of GPT-4.5 also serves as a reminder that the rollout of the elusive GPT-5 has not gone to plan. Persistent rumors indicate that OpenAI has seen diminishing returns in model improvements, suggesting scaling laws (more compute, bigger datasets) for training a model might not equate to improved results.
This is a possible reason why we've yet to see GPT-5 which has been massively hyped. Altman said it will be smarter than him and former CTO Mira Murati who said it will have "Ph.D.-level intelligence." In the meantime, we now have GPT-4.5, which could either be an indication that OpenAI is close to meeting very high expectations or stalling for more time.
Anonymous former OpenAI employees told Fortune that GPT-4.5, internally dubbed Orion, was supposed to be GPT-5, but couldn't achieve enough performance gains to merit the GPT-5 name. Altman said GPT-5 could be expected in a matter of months.
How to try GPT-4.5
As of today, we can start putting GPT-4.5 to the test. Well, not everyone. GPT-4.5 is currently only available to ChatGPT Pro members who shell out $200 a month, with access for ChatGPT Plus subscribers who pay $20 a month, coming out next week. It's only a week apart, but Plus subscribers used to be the top tier granted with early access to new features are now wondering why they even bother paying for a subscription.
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While OpenAI is undoubtedly hoping to gain more Pro subscribers, this could have a backfiring effect by alienating Plus subscribers who suddenly have good options with competitors that are catching up, like xAI's Grok 3, DeepSeek R1, and Anthropic's Claude 3.7 Sonnet.
A lot is riding on GPT-4.5 as an indicator of GPT-5 progress, and now we'll know whether it lives up to the hype.
Cecily is a tech reporter at Mashable who covers AI, Apple, and emerging tech trends. Before getting her master's degree at Columbia Journalism School, she spent several years working with startups and social impact businesses for Unreasonable Group and B Lab. Before that, she co-founded a startup consulting business for emerging entrepreneurial hubs in South America, Europe, and Asia. You can find her on X at @cecily_mauran.
