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What is ChatGPT 4.5?
ChatGPT 4.5, also known as GPT-4.5, and Orion, is one of OpenAI's largest language models. The ChatGPT 4.5 release date was February 27, 2025, when it launched as a research preview. Unlike OpenAI's reasoning-focused models like o1 and o3, GPT-4.5 was built by scaling unsupervised learning — this was done specifically to create a more natural-sounding AI chatbot, writes more similar to humans and features a higher emotional intelligence.
OpenAI described GPT-4.5 as a different kind of intelligence — one that prioritizes pattern recognition, creative insights, and conversational warmth over cold step-by-step reasoning. Altogether, this means that chatgpt 4.5 model is better suited to writing tasks than math, coding, or solving complex logical problems.
This model has broader world knowledge, better understanding of user intent, and significantly fewer hallucinations than its predecessors.
ChatGPT 4.5 New Features
The ChatGPT 4.5 new features focus on making AI interactions feel more natural and human. Here are the key things that set this model apart:
Enhanced emotional intelligence: GPT-4.5 recognizes emotional cues in text and adjusts its tone accordingly, delivering responses that feel genuinely empathetic and understanding.
Reduced hallucinations: OpenAI reports that GPT-4.5 hallucinates at a rate of 37.1% on factual questions, compared to ChaGPT 4o 61.8% — a significant improvement in factual reliability.
Better knowledge and accuracy: The model achieves 62.5% accuracy on SimpleQA tasks, substantially outperforming GPT-4o (38.2%) and demonstrating broader, more accurate world knowledge.
Better understanding of the user intent: GPT-4.5 picks up on subtle conversational cues and implicit expectations, making interactions feel less robotic and more intuitive.
Powerful creative writing: Human evaluators consistently prefer GPT-4.5 over GPT-4o for writing tasks due to its superior style, tone, and creative nuance.
ChatGPT 4.0 vs 4.5 Differences
Understanding the differences between these two models can help you choose the right one for the task you’re trying to solve. While GPT-4o (the 4.0 many users reference) is otpimzed for speed and cost-efficiency, GPT-4.5 is all about delivering the most conversationally advanced chatbot.
Beyond that, GPT-4o was optimized for reasoning tasks, complex STEM problems, and being able to process mixed-media (text, images, audio). It responds quickly and handles technical questions well. GPT-4.5, in contrast, responds more slowly, but its text sounds more natural and human-like.
The key differences include: GPT-4.5 demonstrates higher EQ with warmer, more intuitive responses while GPT-4o provides more factual, direct answers. GPT-4.5 has significantly lower hallucination rates (37.1% vs 61.8%) and broader knowledge accuracy. However, GPT-4o remains much faster, processing responses 5-10 times quicker than GPT-4.5 in many cases.
ChatGPT Plus GPT-4.5 Access
When GPT-4.5 launched, chatgpt plus gpt-4.5 access was limited initially. The model first rolled out to ChatGPT Pro subscribers ($200/month), followed by ChatGPT Plus members ($20/month) about a week later. Enterprise and educational tiers received access in subsequent weeks.
Due to the model's large size and compute requirements, OpenAI cited GPU shortages as the reason for the phased rollout. As of late 2025, GPT-4.5 remains available primarily to Pro users under the Legacy Models tab. If you don’t have a ChatGPT Plus or Pro subscription, you can access this model on Overchat AI through the model selector.
ChatGPT Plus GPT-4.5 Usage Limits
GPT-4o is part of OpenAI's broadeThe chatgpt plus gpt-4.5 users initially received approximately 50 messages per week with GPT-4.5, though OpenAI noted these limits would adjust based on demand and system performance.
Because GPT-4.5 is significantly more compute-intensive than GPT-4o (API pricing is $75 per million input tokens vs $2.50 for GPT-4o), usage limits are substantially stricter. For more access to GPT-4.5, Overchat AI provides an alternative way to chat with this powerful model.
More AI Models by OpenAI
GPT-4o is part of OpenAI's broader ecosystem of GPT models, which includes ChatGPT-5.2 — OpenAI's latest andmost advanced model.
