Everything You Need to Know About OpenAI’s GPT-4.5

Since the beginning of 2025, we have been seeing the launch of one amazing model after another – from DeepSeek-R1 and o3-mini to Grok 3 and Claude 3.7 Sonnet. The latest addition to this ever-expanding list of advanced AI models is the much-awaited OpenAI GPT-4.5. This new model in the GPT series brings “Vibe Check” along with enhanced capabilities to ChatGPT’s chatbot interface. It brings LLM supremacy back to OpenAI as it competes with the latest models like Grok 3 and Claude 3.7 Sonnet. In this blog, we will explore the features of GPT-4.5, its performance, how to access it, and even some hands-on applications. We will also see how it compares with other OpenAI models such as GPT-4o, o1, and o3-mini (high).

What is GPT-4.5?

GPT-4.5 is the latest model by OpenAI and the last model in the GPT series. The first hint of this model was given weeks ago by Sam Altman, when he had released the roadmap for OpenAI. Internally code named ‘Orion’, this is OpenAI’s last “non-chain-of-thought” model. This means that unlike other models like o3-mini, Grok 3, or DeepSeek R1, GPT-4.5 gives direct answers without explaining its reasoning step-by-step.

It relies on learned patterns to produce responses quickly, but may struggle with complex logic-based tasks. It’s trained using “Unsupervised Learning”, to be an inherently intelligent model with better world knowledge. The model also boasts of significantly reduced hallucination rates, along with enhanced contextual knowledge and writing skills. This is why GPT-4.5’s answers sound more natural, without getting over burdened with a lot of reasoning.

Training Approach

Unlike all the latest reasoning models like o1 and o3, GPT-4.5 takes a different training approach. Its core training parts include:

1. Scaled Up Pretraining & Post-training: GPT-4.5 is trained using unsupervised learning at a larger scale, leading to better pattern recognition and world knowledge. The model relies on expanded compute and data for training, along with architectural and optimization improvements.
2. Focus on Unsupervised Learning: The model relies on scaling unsupervised learning to improve factual accuracy and intuition. This leads to reduced hallucination rates and more reliable responses across various topics.
3. Human Collaboration Training: It employs scalable techniques that were developed to train larger models using data derived from smaller models. These methods enhance steerability, making the model better at understanding nuances and following human intent.
4. Reinforcement Learning & Supervision: The model uses Supervised Fine-Tuning (SFT) and Reinforcement Learning from Human Feedback (RLHF) to refine responses. Moreover, additional safety techniques ensure responsible AI behavior and minimize harmful outputs. The model was even stress-tested under OpenAI’s Preparedness Framework before release.

Key Features of GPT-4.5

Now that we have understood the details regarding the GPT-4.5’s training and its core design, let us look at some of its key features:

1. Improved Knowledge & Accuracy: The model outperforms GPT-4o in factual accuracy and has a lower hallucination rate. It excels in SimpleQA benchmarks, showing deeper world knowledge.

2. High Emotional Intelligence (EQ): The conversations with the model feel more empathetic and are more intuitive in nature. The model also showcases better understanding of user emotions and responds appropriately. In other words, the model “knows” when to invite further conversation and when to provide a structured response.

3. Enhanced Creativity & Writing Skills: The model is excellent when it comes to writing, designing, and creative problem-solving. It generates responses that feel warmer and more natural.

4. Faster, More Reliable Responses: It has been optimized for speed and efficiency, delivering faster and more concise answers.
5. Agentic Capabilities: The model showcases better agentic AI capabilities for multi-step coding and automation tasks.

Hands-on Demo

Let us try a couple of prompts and see the results that we get using GPT-4.5.

Prompt: “An emotional synopsis of the life of Alan Turing”

Output:

Prompt: “UGHH! My friend Cancelled on me again!! Write a text message telling them that I HATE THEM!!!”

Output:

GPT-4.5 Benchmarks

We have seen above how the model performs at some tasks; now let us see what the performance numbers have to say. Given below are the benchmark comparisons between GPT-4.5, GPT-4o and o3-mini(high).

• GPQA (science): Measures accuracy in answering general science-related knowledge questions. GPT-4.5 performs significantly better than GPT-4o but lower than OpenAI o3-mini.
• AIME ‘24 (math): Evaluates performance on advanced mathematical problem-solving (similar to Olympiad-level questions). Although the new model improves over GPT-4o, it is far behind OpenAI o3-mini, which excels in reasoning-based math tasks.
• MMMLU (multilingual): Assesses the model’s ability to handle multilingual knowledge tasks. GPT-4.5 leads in multilingual performance.
• MMMU (multimodal): Tests how well the model understands and integrates text with visual inputs. GPT-4.5 outperforms GPT-4o in multimodal tasks.
• SWE-Lancer Diamond (coding): Evaluates AI-generated code performance on complex software engineering challenges. GPT-4.5 performs best in competitive coding, with higher completion rates and associated monetary rewards.
• SWE-Bench Verified (coding): Measures the accuracy of AI in fixing real-world coding issues. OpenAI o3-mini is the best at real-world software engineering tasks, while GPT-4.5 shows improvement over GPT-4o.

Model Comparison: GPT-4.5 vs GPT-4o, o1, and o3-mini

All of OpenAI’s model have their own key features. Here is a table of comparison, listing down the main aspects for the GPT-4.5, GPT-4o, o1 and o3-mini models:

How is GPT-4.5 Different from GPT-4o?

GPT‑4.5 builds on GPT‑4o’s strengths while introducing several key improvements:

• Efficiency & Scale: GPT‑4.5 is engineered to be more computationally efficient. It reportedly delivers over 10× better efficiency in processing compared to GPT‑4o. This means it can handle more complex tasks faster and at a lower cost in some contexts.
• Improved Writing & World Knowledge: Test reports show that GPT‑4.5 offers enhanced writing capabilities with more refined and humanlike personality traits. Its broader and updated training data has resulted in better world knowledge and more contextually relevant, nuanced responses.

• Reduced Hallucinations: One of the most notable upgrades is the reduction in hallucinations. Early tests indicate that GPT‑4.5’s hallucination rate dropped to around 37%, compared to nearly 60% with GPT‑4o.

GPT-4.5 proves to be better than GPT-4o in real-life applications too. The comparative evaluations of GPT-4.5 and GPT-4o with human testers show a preference towards the new model.

For everyday queries, GPT-4.5 wins 57.0% of the time over GPT-4o, suggesting it gives slightly better responses in general knowledge or daily-use questions. When it comes to professional questions, it has a 63.2% win rate against GPT-4o, indicating a significant improvement in handling complex, work-related, or technical questions. Speaking of creative intelligence, GPT-4.5 scores 56.8%, outperforming 4o in creative tasks like writing, ideation, and problem-solving.

Availability of GPT-4.5

Currently, GPT-4.5 will be available to ChatGPT Pro users on web, mobile, and desktop. From next week onwards, it will be available to Plus and Team users and then to Enterprise and Edu users the following week.

GPT‑4.5 has access to the latest up-to-date information with search, supports file and image uploads, and can use canvas to work on writing and code. However, GPT‑4.5 does not currently support multimodal features like Voice Mode, video, and screensharing in ChatGPT.

How to Access GPT-4.5?

To access GPT-4.5, head to www.chatgpt.com.

• Log in to your paid account.
• From the left side corner, at the top, click on the dropdown menu for model selection.
• From the list of models, click on “GPT-4.5”.

How to Access GPT-4.5 Using API?

To access GPT-4.5 using API,

• Go to OpenAI’s API platform.
• Create an account or log in if you already have one.
• Navigate to “API Keys” in your OpenAI account settings.
• Click “Create new secret key” and copy it (you will need it for API requests).

GPT-4.5 is available in Chat Completions API, Assistants API, and Batch API to developers on all paid usage tiers⁠. The model supports key features like function calling, structured outputs, streaming, and system messages. It also supports vision capabilities through image inputs.

Since it’s a bigger model compared to GPT-4o, it incurs more cost, hence do apply caution while working with it!

Applications of GPT-4.5

Now let’s look at how this latest model by OpenAI can enhance our day-to-day workflows. Here are some of its best applications:

1. Streamlined Communication: Efficiently draft professional emails, manage follow-ups, and help schedule meetings.
2. Enhanced Content Creation: Generate and refine marketing content, reports, blog posts, and social media updates.
3. Accelerated Document Analysis: Condense lengthy reports, extract key insights from documents, and create executive summaries.
4. Interactive Training Material: Create interactive learning materials, simulate real-world scenarios, and provide personalized tutoring.
5. Precise Language Localization: Translate documents or communications for global teams while maintaining context and nuance.
6. Automated Customer Support: Provide instant responses, handle FAQs, and customer inquiries with natural, human-like conversation.
7. Improved Coding Assistance: Offer code suggestions, debug errors, or generate documentation to support developers.
8. Simplified Data Interpretation: Assist in generating natural language explanations of complex data sets or analytical reports.

Conclusion

GPT-4.5 is OpenAI’s latest AI model, designed for faster, more accurate, and natural conversations. It improves knowledge accuracy, emotional intelligence, and creativity, making it great for content creation, coding, and automation. Unlike reasoning-focused models, GPT-4.5 gives direct answers and is optimized for speed and efficiency.

Developers can access it via API for advanced AI applications, though it requires more computing power than GPT-4o. While it lacks multimodal voice or video support, its strong benchmarks show major improvements over previous models. On the whole, GPT-4.5 is surely a step forward in AI-human collaboration, making interactions more intuitive and useful.

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Anu Madan

Anu Madan has 5+ years of experience in content creation and management. Having worked as a content creator, reviewer, and manager, she has created several courses and blogs. Currently, she working on creating and strategizing the content curation and design around Generative AI and other upcoming technology.