OpenAI announces GPT-4.5: Bigger, smoother, and pricier than ever

The model is initially available to ChatGPT Pro users and developers, with plans to extend access to Plus and Team users in the coming week.

In a statement, OpenAI described the model as being more ‘natural,’ adding that “its broader knowledge base, improved ability to follow user intent, and greater ‘EQ” make it useful for tasks like improving writing, programming, and solving practical problems. We also expect it to hallucinate less.”

Another difference is the new model’s ability to generate responses directly through large-scale unsupervised learning. OpenAI states that this approach enhances the model's ability to recognize patterns, draw connections, and improve natural interaction.

“GPT‑4.5 has a better understanding of what humans mean and interprets subtle cues or implicit expectations with greater nuance and ‘EQ”. GPT‑4.5 also shows stronger aesthetic intuition and creativity. It excels at helping with writing and design,” the company said.

OpenAI CEO Sam Altman also described the model as providing a more natural conversational experience, though he noted the high computational cost.

“Good news: it is the first model that feels like talking to a thoughtful person to me. I have had several moments where I've sat back in my chair and been astonished at getting actually good advice from an AI. Bad news: it is a giant, expensive model,” Altman wrote in a post on X (formerly Twitter).

Altman also acknowledged temporary limitations in availability due to GPU shortages, stating that OpenAI is expanding its infrastructure to support broader access.

“We really wanted to launch it to Plus and Pro at the same time, but we've been growing a lot and are out of GPUs. We will add tens of thousands of GPUs next week and roll it out to the plus tier then. (Hundreds of thousands coming soon, and I'm pretty sure y'all will use every one we can rack up.) This isn't how we want to operate, but it's hard to perfectly predict growth surges that lead to GPU shortages,” he wrote.

Despite the downsides, the CEO highlighted that “it’s a different kind of intelligence, and there’s a magic to it I haven't felt before. Really excited for people to try it!”

Early benchmark results indicate that GPT-4.5 performs well on general knowledge and conversational tasks but is less effective on STEM-related reasoning assessments compared to other models. However, GPT-4.5 is also pricier. At $75 per million input tokens and $150 per million output tokens, it is 10 times more than Sonnet's Claude 3.7 and 1300% more expensive than GPT-4o.

Looking ahead, OpenAI plans to integrate both pre-training and reasoning-based approaches in the development of GPT-5.

Earlier, OpenAI has also launched Sora, a text-to-video generator that can create short, lifelike video clips from written prompts.