ChatGPT 3.5 launched on March 15, 2023

OpenAI released ChatGPT 3.5 on March 15, 2023, as a free web version that anyone could use without paying. This was the moment ChatGPT became widely known — before this date, the tool existed only as a research preview that required joining a waitlist. The 3.5 version was faster and cheaper to run than the earlier model, which is why OpenAI could offer it free to the public.

The release happened through OpenAI's website at chat.openai.com. Users could sign up with an email address or Google account and start chatting with the AI immediately. There was no download required and no software to install — you just opened a web browser and typed.

This March 2023 release is what most people think of as "when ChatGPT came out," even though the company had shown earlier versions to researchers and a small group of testers before that date.

Key Takeaways

  • ChatGPT 3.5 became publicly available on March 15, 2023, through a free web interface at chat.openai.com.
  • The 3.5 version was faster and less expensive to operate than earlier models, allowing OpenAI to offer it at no cost.
  • Before the public release, ChatGPT existed only as a research preview with a waitlist, so March 2023 marks when ordinary people could actually use it.
  • OpenAI later released ChatGPT 4 in March 2024, which is more capable but requires a paid subscription for most users.

What made the 3.5 version different from earlier ChatGPT models

The main difference between ChatGPT 3.5 and the earlier research preview was speed and cost. The 3.5 model could answer questions much faster — usually in seconds rather than minutes — and it used less computing power, which meant OpenAI could run it without charging users.

ChatGPT 3.5 was also trained on more recent information than some earlier versions. It could understand context better in long conversations, meaning it remembered what you said earlier in a chat thread and could refer back to it. The model made fewer obvious mistakes and could handle more types of questions, from writing code to explaining history to brainstorming ideas.

The earlier research preview had all these same abilities in theory, but the 3.5 version was refined and optimized. Think of it as the difference between a prototype and the first product you can actually buy — the core technology was similar, but the execution was much smoother.

How ChatGPT 3.5 compared to ChatGPT 4

OpenAI released ChatGPT 4 exactly one year later, on March 14, 2024. The 4 model is more capable than 3.5 — it understands more complex questions, makes fewer errors, and can read images as well as text. However, ChatGPT 4 is not free. Most people need a paid subscription to use it, though some limited free access exists.

ChatGPT 3.5 remains available for free and is still the version most people use. It handles everyday tasks well — answering questions, writing emails, explaining concepts, debugging code. ChatGPT 4 is better at specialized work like detailed analysis, creative writing, or solving very complex problems, but the cost difference means many users stick with 3.5.

OpenAI also released a mobile app for both versions in May 2023, a few months after the 3.5 web launch. The app works the same way as the website but is optimized for phones and tablets.

Why March 2023 mattered for AI adoption

The March 15, 2023 release of ChatGPT 3.5 was a turning point because it put a powerful AI tool directly in the hands of millions of people at once. Before this, AI tools were mostly used by researchers, programmers, and companies with technical teams. ChatGPT 3.5 was simple enough that anyone could use it — no coding knowledge required, no special setup.

Within two months of the release, ChatGPT had more than 100 million users. Schools, businesses, and governments started paying attention to what the tool could do. This led to conversations about AI safety, job displacement, and how to regulate AI systems — conversations that are still happening today.

The free availability of ChatGPT 3.5 also forced other companies to build their own AI chatbots. Google launched Bard (now called Gemini), Microsoft integrated AI into Bing search, and other companies followed. The March 2023 release essentially kicked off the current wave of AI tools that people use every day.

Timeline of ChatGPT releases and updates

Understanding the full timeline helps explain where ChatGPT 3.5 fits in the bigger picture. OpenAI first showed ChatGPT to researchers in November 2022, but it was not open to the public yet. People had to join a waitlist and wait weeks or months for access.

On March 15, 2023, the waitlist ended and ChatGPT 3.5 became available to anyone. OpenAI also released an API (a tool for programmers to build ChatGPT into their own software) around the same time, which is why ChatGPT started appearing inside other apps and services.

In June 2023, OpenAI launched ChatGPT Plus, a paid subscription that gave users faster responses and access to new features first. Then in March 2024, ChatGPT 4 arrived. In May 2024, OpenAI released GPT-4o, an even newer model that can handle text, images, and audio. Throughout this time, ChatGPT 3.5 has remained free and available to anyone.

How to access ChatGPT 3.5 today

To use ChatGPT 3.5 right now, go to chat.openai.com in any web browser. You will need to create an account with an email address or sign in with Google or Microsoft. The process takes about two minutes. Once you are logged in, you can start typing questions or requests immediately.

You can also use ChatGPT 3.5 through the mobile app, available on iPhone and Android. The app is free and works the same way as the website. Some third-party apps and services have also integrated ChatGPT 3.5, so you might encounter it in other places depending on what software you use.

If you want to use ChatGPT 4 instead, you will need to pay for a ChatGPT Plus subscription, which costs $20 per month. The free version will always be ChatGPT 3.5 unless you upgrade.

Frequently Asked Questions

Is ChatGPT 3.5 still available for free?

Yes. ChatGPT 3.5 remains free at chat.openai.com and in the mobile app. OpenAI has kept it free since the March 2023 release. You do not need to pay anything to use it, though you do need to create an account.

What is the difference between ChatGPT 3.5 and 4?

ChatGPT 4 is more capable — it handles complex questions better, makes fewer mistakes, and can read images. However, ChatGPT 4 requires a paid subscription. ChatGPT 3.5 is free and still works well for most everyday tasks like writing, answering questions, and explaining concepts.

Did ChatGPT exist before March 2023?

Yes, but not for the public. OpenAI showed ChatGPT to researchers in November 2022 and let a small group of people test it through a waitlist. March 15, 2023 is when anyone could use it without waiting, which is why that date is considered the real launch.

Can I use ChatGPT 3.5 on my phone?

Yes. OpenAI released a mobile app in May 2023 that works on iPhone and Android. The app is free and gives you the same ChatGPT 3.5 experience as the website, but optimized for smaller screens.

Why did OpenAI make ChatGPT 3.5 free?

The 3.5 model was designed to be fast and cheap to run, so OpenAI could offer it without charging users. This strategy helped millions of people discover ChatGPT quickly. OpenAI makes money through ChatGPT Plus subscriptions and through an API that programmers and companies pay to use.