ChatGPT is a chat application made by OpenAI. You type (or speak), it replies with text, and it can also read files, look at images, search the web and run small pieces of code. The product is free to start at chatgpt.com, with paid plans that unlock stronger models and more usage.
Under the hood, ChatGPT is a front end for OpenAI's GPT language models. The same models are sold separately through the OpenAI API, where developers pay per token instead of per month. Keeping those two things apart, ChatGPT the product and GPT the models, is the first step to not overpaying, because they are priced completely differently.
How it works, in one paragraph
A GPT model does not look up answers. It was trained on a very large amount of text to predict the next word (technically the next token) given everything that came before. When you ask a question, it produces the most plausible continuation, one token at a time. That is why it is fluent even when it is wrong, and why a vague prompt gets a vague answer: the model is continuing what you gave it.
What ChatGPT is genuinely good at
- Drafting and rewriting — emails, proposals, cover letters, summaries, tone changes. This is the highest-value use for most people.
- Explaining things — turning a dense document, a contract clause or an error message into plain language.
- Structuring messy input — turning notes into an agenda, a transcript into action items, a spreadsheet dump into a table.
- Code help — writing small scripts, explaining code, fixing errors, converting between languages.
- Thinking partner — listing options, spotting gaps in a plan, arguing the other side.
Honest limits
It can state false things confidently, including invented citations, statistics and product prices. It does not know anything that happened after its training data unless it searches the web or you paste the source in. It is not a calculator by default, and it can lose track of details in very long conversations. None of these are fatal, but each one has a workaround you will learn in this course.
A note on cost from the start: ChatGPT Free costs $0. The question this course keeps coming back to is not "is ChatGPT worth it" but "which version of ChatGPT is worth it for the amount I actually use". You can check the current plan lineup on our ChatGPT pricing page at any point.
Knowledge check
Which statement about ChatGPT is correct?