GPT-4 is a large language model built by OpenAI, while ChatGPT is the chatbot app people use to talk to such models. Think of GPT-4 as an engine and ChatGPT as the car. GPT-4 launched on 14 March 2023 and powered ChatGPT’s paid plan, but OpenAI replaced it inside ChatGPT in 2025.
That is the short answer. The longer one matters because many people still use the two names as if they mean the same thing, and the products have changed a great deal since 2023. This explainer covers what made GPT-4 different, how ChatGPT works today and where GPT-4 fits in the 2026 picture.
GPT-4 vs ChatGPT: the core difference
ChatGPT is a product. It is the website and app, available on Android, iOS and the web, where you type or speak a question and get an answer. It has features around the model, such as chat history, file uploads, image generation, voice mode and memory.
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GPT-4 is a model. It is the trained system that reads your prompt and produces the reply. When ChatGPT launched on 30 November 2022, it ran on a model from the GPT-3.5 series. In March 2023, paying users could switch to GPT-4. So the real comparison readers search for is usually GPT-4 against the GPT-3.5 model that powered free ChatGPT at the time.
Quick facts
| Item | ChatGPT | GPT-4 |
|---|---|---|
| What it is | Chatbot app and website | Large language model |
| Made by | OpenAI | OpenAI |
| Launched | 30 November 2022 | 14 March 2023 |
| Input | Text, voice, images, files (depends on plan) | Text and images |
| Status in October 2026 | Active, now running the GPT-6 family | Removed from ChatGPT in 2025 |
What made GPT-4 unique when it launched
1. It could read images
Earlier GPT models handled only text. OpenAI described GPT-4 as a large multimodal model because it could accept an image along with text and answer questions about it, for example explaining a chart or describing a photo. Image input reached ordinary ChatGPT users later in 2023.
2. Better reasoning on tests
OpenAI reported that GPT-4 showed human-level performance on many professional and academic benchmarks. Its best known example was a simulated bar exam, where OpenAI said GPT-4 scored around the top 10 per cent of test takers, while GPT-3.5 scored around the bottom 10 per cent.
3. Longer memory within a conversation
The standard GPT-4 model had a context window of about 8,000 tokens, with a special version supporting about 32,000 tokens. That let it work with long documents that GPT-3.5 could not hold in one go. GPT-4 Turbo, announced in November 2023, raised this to 128,000 tokens and cut prices for developers.
4. Fewer made-up answers, but not zero
OpenAI said GPT-4 was more reliable and followed complex instructions better than GPT-3.5. It still made factual mistakes, known as hallucinations, and OpenAI warned users to check important answers.
How GPT-4 was used in ChatGPT
In 2023, free ChatGPT users got GPT-3.5, while ChatGPT Plus subscribers could pick GPT-4, with a cap on how many messages they could send in a few hours. Early users shared examples of GPT-4 writing code for simple games, turning a hand-drawn sketch into a working web page and drafting recipes from a photo of ingredients.
Developers could also reach GPT-4 directly through OpenAI’s API and build it into their own apps. Microsoft, OpenAI’s biggest investor, used GPT-4 class models in Bing Chat, which later became Copilot.
What happened to GPT-4 after 2023
GPT-4 was replaced step by step. Here is the timeline that matters for anyone reading old guides:
- May 2024: OpenAI introduced GPT-4o, a faster model that handles text, audio and images, and made it available to free users too.
- April 2025: OpenAI said GPT-4o would replace the original GPT-4 in ChatGPT by the end of that month. GPT-4 stayed available to developers through the API.
- August 2025: GPT-5 arrived and became the main model in ChatGPT.
- February 2026: OpenAI retired several older models from ChatGPT, including GPT-4o, GPT-4.1 and the original GPT-5, as reported by Thurrott.
- October 2026: According to OpenAI’s release notes, GPT-6 launched in ChatGPT on 7 October 2026. Paid plans get GPT-6 Sol, while Free and Go users get GPT-6 Luna.
So if you open ChatGPT today, you are not using GPT-4. The app name stayed the same while the model underneath changed several times.
Why the GPT-4 vs ChatGPT question still matters
Many articles, courses and office policies written in 2023 still say things like “use ChatGPT for free, pay for GPT-4”. That advice is outdated. Free users in 2026 get a much stronger model than the original GPT-4, though paid plans still offer higher limits and the most capable versions.
It also helps when you read news about AI. A headline about a new GPT model is about the engine. A headline about ChatGPT features, such as voice, shopping or group chats, is about the app. Indian readers using AI for study or work can follow more of these changes in our technology section.
Competition around ChatGPT
GPT-4 also pushed rivals to move faster. Google launched Bard in 2023 and later renamed it Gemini. Anthropic’s Claude, Microsoft’s Copilot, Meta AI and Chinese models from companies such as Alibaba and Baidu now compete for the same users. In India, several of these assistants are built into phones, messaging apps and search, so many people use a GPT-style model without opening ChatGPT at all.
For students, the practical advice stays the same across all of them: use AI to understand and practise, check facts from official sources and follow your institution’s rules. Our education coverage tracks how colleges and exam bodies are responding.
Frequently asked questions
Is GPT-4 the same as ChatGPT?
No. GPT-4 is an AI model, and ChatGPT is the app that runs OpenAI’s models. GPT-4 powered ChatGPT’s paid tier from March 2023 until OpenAI replaced it in 2025.
Can I still use GPT-4 in ChatGPT in 2026?
No. OpenAI moved ChatGPT from GPT-4 to GPT-4o in 2025 and has since moved to the GPT-5 and GPT-6 families. Developers can still find GPT-4 in OpenAI’s API, according to Wikipedia’s entry on the model.
What is the main difference between GPT-4 and GPT-3.5?
GPT-4 could read images as well as text, handled longer documents and scored much higher on exams such as OpenAI’s simulated bar exam test.
Which model does ChatGPT use now?
As of 7 October 2026, OpenAI’s release notes say paid plans use GPT-6 Sol and Free and Go plans use GPT-6 Luna.
Sources: OpenAI ChatGPT release notes, OpenAI GPT-4 research page, Wikipedia: GPT-4, Thurrott on 2026 model retirements.
