A Guide to ChatGPT Models and Their Best Applications

As time has gone on, OpenAI has introduced various AI models to ChatGPT, evolving from traditional GPT-series large language models (LLMs) to advanced reasoning models within the o-series. While being able to choose a model that fits your needs is useful, it can also confuse general users. This article aims to clarify the different ChatGPT models so you can select the best one for your specific task. Let’s dive into the details of the ChatGPT models.

ChatGPT o3

The o3 model on ChatGPT is a reasoning-focused AI model and is currently OpenAI’s most advanced option. This full o3 model shines in areas like coding, mathematics, science, and visual analysis. It’s particularly suitable for STEM (Science, Technology, Engineering, and Math) questions and visual tasks. You can challenge the o3 model with even the most intricate queries, and it will take some time—possibly several minutes—to provide a comprehensive answer.

Moreover, it operates as a multimodal model, allowing you to upload images, charts, and diagrams. Its visual perception capabilities are remarkably strong; it can identify specific locations by analyzing images. Additionally, o3 functions as an agentic model, giving it the ability to utilize various tools within ChatGPT, such as the Python interpreter, web browsing, file analysis, and image generation to formulate thorough responses.

The o3 model is available exclusively for ChatGPT Plus and other paid subscription plans, accessible from the ChatGPT dropdown menu.

ChatGPT 4o

ChatGPT 4o (or GPT-4o) serves as OpenAI’s standard model for a wide array of tasks. While it may not be the top performer in every domain, it does well in general. GPT-4o is optimized for conversations and excels in everyday chat scenarios. For creative tasks—like writing, summarizing, chatting, and translating—GPT-4o outperforms reasoning models from the o-series.

However, when it comes to STEM-related topics such as coding, math, and science, GPT-4o trails behind the o3 model. Interestingly, GPT-4o is fully multimodal and is utilized for multiple functionalities in ChatGPT. It powers the built-in image generation feature and the Advanced Voice Mode.

For example, the viral Ghibli images are generated using the GPT-4o model. Additionally, features like Live Video, which enables users to share their camera or screen for real-time interactions, rely on GPT-4o. The model can also analyze uploaded files and images, browse the web, perform advanced data analysis with Python, and aid in creating custom GPTs. Moreover, the Operator AI agent utilizes the visual capabilities of GPT-4o.

In summary, GPT-4o is the primary model on ChatGPT for a wide range of functions and is accessible to both free and paid users. Free users will be switched to a less powerful mini version of GPT-4o once their usage limit is reached.

ChatGPT 4.5

GPT-4.5 is OpenAI’s largest non-reasoning LLM and is currently in a research preview, exclusive to paid subscribers. This model excels especially in creative writing, outperforming all other models. It can discern patterns from complex prompts, make connections, and produce creative insights without relying on reasoning.

OpenAI claims that GPT-4.5 has a higher “Emotional Quotient” (EQ) that enhances the naturalness of interactions. It’s also noted for its humor compared to other models. This model is ideal for enhancing writing and programming tasks. However, due to GPT-4.5’s considerable size, OpenAI has excluded it from the API; still, paid users can find it listed under “More models” in ChatGPT.

ChatGPT o4-mini

The o4-mini model is the successor to the o3-series, designed for quick and cost-effective reasoning tasks. While it’s smaller in size, o4-mini performs remarkably well in math, coding, and visual tasks, often surpassing the larger o3 model for these activities.

The o4-mini model also competes well in visual tasks. While the o3 model benefits from being trained on a larger base, the compact o4-mini is still quite capable. The o4-mini-high variant, which uses additional computing resources and processing time, excels even further in coding and visual analysis.

Due to its smaller size and strong performance, OpenAI has made the o4-mini model available to free users, replacing the previous o3 mini model. You can use the o4-mini model for STEM-related questions, coding challenges, and complex problems by clicking the “Extended thinking” button in the free version of ChatGPT.

ChatGPT 4.1

OpenAI has recently rolled out the GPT-4.1 model for developers in the API, and it has now been introduced to ChatGPT. This model is tailored for programmers seeking improved instruction-following capabilities and a larger context window. Unlike reasoning models, GPT-4.1 is recommended for coding tasks due to its faster and more cost-effective performance.

GPT-4.1 supports a context window of up to 1 million tokens and performs exceptionally well on lengthy tasks. Additionally, it has a fresh knowledge cutoff as of June 2024. Smaller variants, such as GPT-4.1 mini and nano, offer decent coding performance at a more affordable rate.

If you’re looking for a faster, non-reasoning AI model for coding, the GPT-4.1 model in ChatGPT is your best option, but keep in mind that it’s available only to paid users.

ChatGPT o1 pro

With the introduction of the o3 and o4-mini models, the o1 pro mode might be overlooked, yet it remains a powerful reasoning model derived from the original o1 model. It functions as a high-compute mode, utilizing additional resources to tackle more challenging math, science, and coding problems.

The o1 pro mode can spend several minutes to analyze intricate problems and derive solutions. Given its resource-intensive nature, it’s available only to ChatGPT Pro subscribers, which costs $200 a month. OpenAI has also announced an upcoming high-compute o3 pro mode that will replace the o1 pro for Pro users.

Codex-1

For programmers, OpenAI has introduced Codex, a new cloud-based software engineering AI tool powered by the Codex-1 model, which is based on the o3 reasoning model and fine-tuned for coding tasks. OpenAI has trained this model using reinforcement learning on real-world coding tasks to produce code that closely aligns with human style and preferences.

Codex can generate code, add features, run tests, validate outputs, create pull requests, and much more. OpenAI states that Codex-1 is its most proficient coding AI model. While it’s not directly integrated within ChatGPT, you can access this model from the ChatGPT sidebar. Keep in mind that you’ll need a subscription to ChatGPT Pro or a higher tier to utilize this AI agent and model. ChatGPT Plus users will have access soon.

In conclusion, these are the current AI models available in ChatGPT, each suitable for different tasks. I recommend using GPT-4o for everyday inquiries, and the o3 model for STEM-related requests and coding challenges. Free users can take advantage of the “Extended thinking” button to access the impressive o4-mini reasoning model.

Lastly, OpenAI has phased out the DALL-E image generation model from ChatGPT. However, you can still use it as a custom GPT via this link. Additionally, OpenAI offers the Sora AI model for crafting AI videos, although it is separate from ChatGPT. Finally, the Deep Research AI agent runs on a specialized version of the o3 reasoning model.