The fourth generation of GPT models
GPT-4 is historically OpenAI’s fourth major language model, but it is no longer the latest model. OpenAI is currently focusing on further developing the GPT-5 generation with the GPT-5.5 model.
“GPT-4 can solve difficult problems with greater accuracy thanks to its greater general knowledge and problem-solving capabilities.”
— OpenAI, GPT-4 Release Notes
Accuracy, multimodality and integration into business processes are key features of the models. The GPT-4 family (including GPT-4o with multimodal processing and high accuracy in text and code) marked OpenAI’s breakthrough into professional-grade AI performance, but was superseded by GPT-5 (August 2025) as a unified, adaptable system with integrated reasoning. GPT-5.2 further optimises this with a more conversational tone and faster reasoning.
The end of the GPT-4 model family
GPT-4o and earlier versions: These models were removed from the ChatGPT user interface on 13 February 2026. GPT-4o and GPT-4.1 will remain available via the OpenAI API, even though they have been removed from the chat interface. However, compared to the new GPT-5 models, these models are nowhere near as powerful or efficient. According to OpenAI, the new version delivers more precise results and detects logical errors more reliably. This opens up new interface and application possibilities for businesses. The announcement caused a stir among users online, as GPT-4o in particular was praised for its creative writing style and high emotional intelligence. Users reacted with disappointment, and posts received a high number of comments regarding its use. Users are campaigning in various forums for the model to be retained. A major point of criticism is that OpenAI gave very little notice of the discontinuation and failed to honour previous commitments (e.g. that GPT-4o would not be discontinued). Further concerns include uncertainty regarding stability and long-term investment security, as GPT-4o was often used in work processes. Due to the protests, reports suggest that older models such as GPT-4o and o3/o4-mini can now be partially reactivated in the settings for paying users (‘show all models’). However, the GPT-5 series largely replaces these models, and OpenAI’s focus is now on GPT-5.5 Thinking and GPT-5.4 mini.
We have compiled everything about OpenAI’s GPT-5 release in our article “GPT-5: everything you need to know about the latest model at a glance”.
To better understand the progress of the models, however, it’s worth taking a look back. That’s why we’re providing you with an overview of GPT-4 here. What were the strengths of GPT-4 and GPT-4o, and how do these models differ from GPT-5 today?
What was GPT-4 able to do?
“GPT-4 is a large multimodal model (accepts image and text input, gives text output) which, although less capable than humans in many real scenarios, demonstrates human performance on various professional and academic benchmarks.”
According to OpenAI, GPT-4 shows strong performance in various benchmarks and as a multimodal model in general. OpenAI addresses the following three core areas in particular:
- Creativity: GPT-4 is creative and collaborative and can create, edit, and repeat creative and technical writing tasks with users, such as composing songs, writing screenplays, or learning a user's writing style
- Visual inputs: GPT-4 can accept images as input and generate labels, classifications, and analyses.
Example: If you upload an image showing flour, eggs, butter, and milk, GPT-4 is able to suggest what you can do with these foods - Longer context: GPT-4 is able to process large context windows, which enables use cases such as creating long-form content and conversations, and searching and analyzing documents. The context windows vary depending on the GPT-4 model: GPT-4 Turbo and GPT-4o support up to 128,000 tokens. Newer variants such as GPT-4.1 (April 2025) extend this to 1 million tokens in the API version, optimized for long documents and code bases.
More abilities
- GPT-4 can identify humor:
During the initial presentation of GPT-4, an example of AI's understanding of humor was shown. It should be borne in mind that humor is very abstract and even among people it is often discussed what counts as humor and what does not. So the fact that AI can identify humor — or take steps in that direction — is a major milestone. During the presentation by OpenAI, the sense of humor was presented using an example: GPT-4 was able to describe why a comic shown was considered funny. - GPT-4 can check contracts and detect errors:
In this way, GPT-4 was able to immediately find weaknesses in an Ethereum contract within a few seconds. - Create parts of program code:
Extending existing code to include requirements works very well: For example, changing and creating database queries - Documenting program code:
Documenting program code adequately and well is sometimes a time-consuming task that can ideally be taken over by GPT-4 — as internal tests carried out by us have shown.
What could GPT-4 not do?
Similar to GPT-3 in conjunction with ChatGPT, this generation also has the problem that artificial intelligence sometimes comes up with content and presents it as facts. These are known as hallucinations. It is also important to always carry out a fact-check at this point before trusting the information provided and disseminating it to others. The lexicon article provides more background information:”Wrong answers from AI? This is how AI hallucinations occur.”
What has distinguished GPT-4 for a long time, solid language understanding, strong text and code generation and the first multimodal capabilities, today represents the basic technological requirement to the next generation of models, GPT-5. The requirements for AI systems have increased significantly and users no longer just expect correct answers, but comprehensive information with deep reasoning, high reliability and, above all, faster responses. The spin-off of GPT-4 does not mark a step backwards, but a transition to AI systems that are significantly more focused on Productivity and collaboration are designed.
How can the GPT models be used?
For anyone using ChatGPT for free, the default model has changed from August 2025 onwards to GPT-5 as the primary model. If the free request limit is exceeded when using GPT-5, the resource-efficient variant GPT-5 mini is used as the default fallback model. When the free request limits are reached, the performance-optimised mini version (GPT-5 Mini) is used as a fallback. With its 2026 pricing model, ChatGPT clearly positions itself as a freemium product, with tiered performance levels:
What does GPT stand for?
GPT stands for “Generative Pre-trained Transformer” and refers to a family of large neural networks developed by OpenAI to handle natural language processing tasks such as word generation, translation, and text classification.
What is GPT-3?
GPT-3 is a model in the GPT series and was released in 2020. It was the largest and most powerful language model on the market before GPT-4 and GPT-4o. GPT-3 has achieved impressive results in many NLP tasks such as translation, text completion and question-answer tasks, and is therefore an important milestone in the development of artificial intelligence and natural language processing.
GPT-4 vs. GPT-3
According to OpenAI, GPT-4 is a significant increase over the previous model:
“We spent 6 months making GPT-4 more secure and customized. According to our internal analysis, GPT-4 is 82% less likely to respond to requests for illegal content and 40% more likely to provide factual answers than GPT-3.5. ”
The self-test also shows that GPT-4 seems much more complex and intelligent. CEO Patrick Zimmermann has tested the new model himself and is convinced:
“GPT-4 understands more complex queries better. You can include a lot of context in the prompt; the so-called instructions can be significantly more complex than before.”
- Patrick Zimmermann, CEO of MoinAI
Why is that: GPT-3, which was considered the largest language model at the time, was trained with 175 billion parameters. By way of comparison, GPT-4 is trained with 100 trillion parameters.
Which is better?
There is no uniform recommendation as to which model is more suitable, as both GTP-3 and GTP-4 each have advantages and disadvantages. GTP-3 is often the better choice for simpler tasks, while GTP-4 is preferred when higher accuracy is important for more complex tasks.
What is GPT-4o?
gPT‑4o Is a multimodal development of GPT-4, where the “o” stands for “omni.” It was released in May 2024 and is now only available to paying users via API or model selection. At the presentation, OpenAI particularly emphasized the advanced capabilities for context-rich and creative tasks, such as multimodal interactions or chatbots with audio/image input from GPT-4o. The model also increased the token capacity. In terms of performance, speed and the quality of responses, the model far surpassed its predecessors.
GPT-4 vs. GPT-4o
With the release of GPT-4o, the first question was whether the new model would now replace GPT-4. It is now clear that GPT-4o is not just an addition, but has completely replaced GPT-4 in the ChatGPT interface. Since April 30, 2025, GPT-4o has therefore been the new standard model.
GPT-4o scores particularly well with higher speed and lower costs compared to GPT-4. In addition, it offers features that GPT-4 did not natively support, such as processing images and audio. In benchmarks such as MMLU and HumanEval GPT-4o performs better and is particularly convincing for multilingual and visual tasks according to OpenAI (as of summer 2025).
GPT-4, on the other hand, has long offered the clear advantage that it can reproduce data in real time at any time because it has permanent access to the Internet. But since a new update, GPT-4o now also has permanent access to the Internet and even with the free version GPT-5-mini, users can now have data provided in real time (provided that web access is activated for the respective chat session).
What is GPT-4.1?
GPT-4.1 is an OpenAIS model series (Standard, Mini, Nano) and has been in use since April 2025. In contrast to GPT-4o, which has been optimized for broad multimodality (text, image, audio, video), GPT-4.1 focuses on precision, reliability and technical tasks — particularly in the area of programming and web development.
GPT-4.1 was originally only provided via the API and was particularly popular with developers there. Due to high demand, it is now also available in ChatGPT via the model selection (“Other models”) — for users with a Plus, Pro or Team plan. The model offers similar usage limits as GPT-4o, but according to OpenAI, impresses with even more accurate following of instructions, improved coding capabilities and more stable performance for complex tasks.
In addition, a more compact version was also released: GPT-4.1 mini. Since May 2025, it has replaced the previous GPT-4O mini model as a standard fallback for free accounts as soon as their GPT-4O limit is reached.
What is GPT-4.5?
GPT-4.5, also known internally as “Orion,” was an intermediate model between the GPT-4 and GPT-5 family, which was presented by OpenAI in February 2025. The model should be particularly strong for everyday questions, texts and summaries, while complex logic and programming were not in focus.
The model was used as “Research Preview” published and was initially available primarily for paying users (Pro, later also Plus/Enterprise), but was already available in August 2025 completely discontinued. The reasons were too high costs and an excessively computationally intensive model that was only intended for research but did not perform at frontier level. API access definitely ended on July 14, 2025 with the migration to GPT-4.1, a more efficient and cost-effective variant.
What is GPT-5?
As of January 2026, GPT-5 is OpenAI’s latest and most powerful generation of AI. According to the manufacturer and current benchmarks, the models in this family are more intelligent across the board and provide more accurate and useful answers in programming, mathematics, text processing and more. Particularly noteworthy is the ‘reasoning’ capability, which enables complex tasks to be analysed and solved in greater depth. Other new changes (as of January 2026) include:
- Automatic model router: Dynamically selects between Instant (fast) and Deep-Thinking depending on the query
- Proactive AI agent: Automatically handles tasks, including, for example, calendar management or code generation
New models further optimise the conversational tone whilst simplifying the personalisation of ChatGPT. GPT-5.5 shows significant improvements in reasoning, document and context understanding, professional knowledge work and technical tasks. OpenAI positions GPT-5 as an “AI expert for everyone”. It is designed to improve collaboration between humans and AI by not only providing answers, but also asking relevant follow-up questions and delivering interactive outputs, thereby making the work process more efficient.
GPT-4o vs. GPT-5
Compared to GPT-4o, GPT-5 is making significant progress in several key areas, according to OpenAI:
- Intelligence and accuracy: GPT-5 provides more reliable results in all areas of application. It shows noticeable improvements, especially when it comes to complex tasks such as code debugging or financial analysis → GPT-5 makes at least 20% fewer factual errors than GPT-4o.
- “Thinking” and Reasoning: A key feature is the improved ability to address problems in a structured manner and to solve tasks that previous models often worked on incorrectly.
- Less “yes-man” behavior: GPT-5 is less likely to blindly agree to user input. It is able to identify and correct logical errors in the user's prompt.
- multimodality: Like GPT-4o, GPT-5 also processes text and images. However, the interpretation of visual content is even more precise and flexible.
- Adaptability for companies: GPT-5 can work better with internal company data by accessing files (if unlocked) via integrated apps such as Google Drive or SharePoint.
After publication, there was both very positive feedback on intelligence and accuracy as well as criticism regarding writing style and interaction length compared to GPT-4o. OpenAI then made adjustments.
Comparison of current GPT models: Which version is suitable for what?
The following overview shows the current ChatGPT models, including strengths, fields of application and usage limits:
What should be considered when using GPT models?
As already mentioned above, it is important to verify information that has been issued, packaged as facts — this remains the case even with the successor to the GPT-4 series. In addition, the output of the AI, the answer that ChatGPT provides, is only as good as the input. This means that if the prompt, i.e., the request that the voice model receives via chat, is not sufficiently well described, the result is correspondingly vague. The more precisely and better the prompt is formulated, the higher the quality of the GPT response. And don't forget: A fact check never hurts to make sure that the information is correct and isn't hallucinating.
AI chatbot for customer communication
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