GPT-4.5 is a research preview version of the large-scale chat model launched by OpenAI. It focuses on broader knowledge, more natural dialogue, stronger creativity and lower hallucination rate. It supports search, file upload and image input.

Full review of GPT-4.5

Core parameters and statistics

Project	Specifications
Product Positioning	Research Preview Large Chat Model
Developer	OpenAI
API Pricing	$75/million input tokens, $150/million output tokens
Available Channels	ChatGPT (Pro preferred) + API
Core Metrics	SimpleQA accuracy 62.5%, hallucination rate 37.1%
Multi-modal	Image input + file upload
Applicable scenarios	Writing, programming, creativity, learning Agent

GPT-4.5 is not OpenAI's "inference" model (that's the o series), but an upgrade of the "chat" model - a route closer to GPT-4o than o1/o3. What it pursues is a more natural and empathetic conversation experience, not the accuracy of math competition questions.

User and market recognition

The first users of GPT-4.5 are ChatGPT Pro subscribers, and will later be expanded to Plus, Team, and Enterprise. Its positioning is differentiated from the o-series reasoning models - the o-series is used for complex tasks that require deep reasoning, and GPT-4.5 is used for daily conversations, writing, creativity, and scenarios that require "high emotional intelligence" responses.

Publicity verification: OpenAI emphasizes GPT-4.5's "high emotional intelligence" and "more natural" conversation experience. This direction indeed differentiates it from the o series. But "high emotional intelligence" is more reflected in the friendly tone and tactful replies, which does not mean that GPT-4.5 has made a qualitative leap in factual accuracy - its SimpleQA accuracy rate of 62.5% and hallucination rate of 37.1% indicate that it still makes mistakes and requires manual verification in scenarios that require accurate facts.

Expert View: The value of GPT-4.5 is that it fills a gap in the OpenAI product matrix-between "fast conversation model" and "deep reasoning model". GPT-4o is adequate for daily conversations but not amazing, and the o series is "overthinking" for simple tasks and expensive. GPT-4.5 wants to be the middle option that is "just a little more useful and just a little more expensive".

Cost advantage

Billing dimensions	Price
API Input	$75/million tokens
API Output	$150/million tokens
ChatGPT Pro	$200/month (includes priority access)
ChatGPT Plus	$20/month (open gradually)

The pricing is significantly higher than GPT-4o, but lower than the inference pricing of the o1 series. For generative tasks that require high-quality natural dialogue (writing, translation, content creation), GPT-4.5 has a reasonable cost-to-output ratio; for simple queries, it is more economical to use cheaper models.

Free Truth: GPT-4.5 does not have a free tier. Free users of ChatGPT are limited to models such as GPT-4o mini. Pro subscribers ($200/month) get priority access, and API users pay as you go. Evaluating GPT-4.5 requires paid testing on the API.

Main functions

• More natural dialogue: GPT-4.5 is closer to human dialogue mode than GPT-4o in terms of intention understanding, emotion perception and context grasp. To put it simply - it "understands human language" better and can understand the underlying meaning.
• Low hallucination rate: The hallucination rate of 37.1% on SimpleQA is a significant improvement over the previous generation model. This means less misinformation in scenarios that require factual accuracy (e.g. study tutoring, information seeking).
• Creative Writing: Perform better on creative tasks such as story creation, copywriting, and brainstorming. There is no standard answer for "good" creative tasks. The advantage of GPT-4.5 lies in the naturalness and richness of the output content.
• Multi-modal support: Supports image input understanding, file upload analysis, and canvas writing and coding collaboration.

Model and version evolution

Version node	Time	Key changes	Current significance
GPT-4o	~2025	Establish a multi-modal main model route	Taking into account cost, speed and universal capabilities
GPT-4.5 Research Preview	~2026-06	Strengthen knowledge, conversational naturalness and creative output	Advance the "chat experience" from usable to more like real-person communication

The positioning of GPT-4.5 version is very clear. It is not a branch of the o series that emphasizes long-chain reasoning, but a quality improvement on the GPT-4o route. OpenAI uses the label "Research Preview" to essentially tell developers that this is an experimental main candidate for high-quality interaction scenarios, rather than the cheapest or safest default option for all scenarios.

The current version is more like a capability verification node. What it verifies is whether "more natural dialogue and less illusions" can alone constitute a product premium, rather than continuing to rely solely on stacking multi-modal or contextual length to grab attention.

Technical advantages

Technical points	Mechanism of action	Actual effects
Stronger unsupervised pre-training	Expanded knowledge coverage and language refinement	Chatting, writing and complex expressions more naturally
Post-training alignment enhancements	Optimized for tone, empathy, and factuality	More suitable for high-frequency conversations and content polishing
Multi-modal input continuation	Support image and file input	Unify general chat and lightweight analysis in one model
Accuracy/Illusion Rate Improvement	Pursuing factual improvements on public benchmarks	Learning coaching, Q&A and assistant scenarios are more controllable

The competitive point of GPT-4.5 is not "solving the most difficult problems", but "making most of the conversational tasks in daily work smoother". Compared with the inference-oriented model, it lacks some mathematical and strict chain derivation advantages, but in exchange for a smoother language organization and a less mechanical feel, which is more important for writing, communication, and customer support tasks.

Publicity Verification: The official SimpleQA accuracy rate of 62.5% and hallucination rate of 37.1% are signs of improvement compared to the previous generation, but they cannot be directly equated to being more reliable in all business scenarios. For fact-intensive tasks, it is indeed more stable than the early chat model; but for high-risk decision-making, professional compliance and complex logic problems, external verification or the use of reasoning models is still needed.

How to use

• Web client: You can use it by visiting the official website and registering an account. Most functions do not require installation.
• API access: Provides RESTful API, developers can obtain the API Key and integrate it into their own applications.

Product Pricing

The pricing model is subject to the official real-time page. Usually a freemium or subscription system is used, and basic functions can be used for free. Advanced functions or high-frequency use require paid subscriptions, and users are advised to evaluate the optimal solution based on actual usage.

Application scenarios

• Daily Writing and Polishing: Content generation and polishing of emails, reports, and articles. The "natural feeling" of GPT-4.5 has obvious advantages in writing scenarios that require a human touch.
• Study Coaching and Q&A: Explain complex concepts in a more understandable way. The low hallucination rate makes GPT-4.5 more reliable than previous generations in learning scenarios.
• Brainstorming and Idea Generation: From marketing ideas to product naming, GPT-4.5 demonstrates stronger creativity in scenarios that require divergent thinking.

Dissuade scenario: If mathematical reasoning, logic puzzles or complex coding debugging are required, inference models such as o3 or o4-mini are better than GPT-4.5 in accuracy. GPT-4.5 is a "chat champion" rather than a "problem-solving champion".

Applicable people

• Content Creators: Writers, editors and marketers who need high-quality text generation, GPT-4.5 outperforms GPT-4o in tone control and naturalness.
• ChatGPT Heavy Users: Professionals who use ChatGPT to assist their work every day, Pro subscribers can experience it first. For tasks such as daily writing, brainstorming, and email polishing, GPT-4.5 brings a conversational experience closer to that of a human assistant.
• API Developers: Developers who build applications that require a natural conversational experience and are willing to pay higher prices for higher quality model output. It should be noted that the pricing is several times higher than GPT-4o, and the input-output ratio needs to be evaluated.
• Product Teams: Teams looking for a middle path between "fast response" and "deep reasoning", GPT-4.5 fills this gap.

Current Limitations: GPT-4.5 is inferior to o-series reasoning models in precise mathematical reasoning, multi-step logical reasoning, and factual accuracy. If the core of the task is "get it right" rather than "make a good conversation", the o series should be given priority.

Summary and Outlook

It provides competitive solutions in its field, and its core value lies in lowering the threshold for AI use in this field.

Current limitations: Some advanced features require paid subscription, and the free version has function or usage restrictions; specific technical details and performance benchmarks have not yet been fully disclosed.

Related tools: DeepSeek, ChatGPT

Version Info

• GPT-4.5 ：Research the preview version to improve the knowledge and naturalness of conversations and reduce the rate of hallucinations. （~2026-06）
• GPT-4o ：The main model of the previous generation. （~2025）