What is the difference between GPT and an LLM?

GPT is a specific family of large language models, while LLM is the general category — so every GPT is an LLM, but not every LLM is a GPT. It's a brand-versus-type distinction, a bit like the difference between Kleenex and tissues.

LLM vs. GPT: what's the difference?

LLM (large language model) describes any AI model trained on huge amounts of text to understand and generate language. GPT — Generative Pre-trained Transformer — is the specific line of models OpenAI built, the ones that power ChatGPT. Here's the quick version:

Why do people confuse them?

It's mostly history. GPT models, especially through ChatGPT, made LLMs famous, so GPT became many people's shorthand for the whole technology. Underneath, though, the core design — the transformer architecture and next-word prediction — is shared across essentially all modern LLMs, GPT included.

That shared foundation is why the models feel similar to use even when they come from rival companies.

Why does the distinction matter?

Knowing which word someone means keeps you from comparing tools inaccurately. If a product says it uses an LLM, that's a general statement — it could be any model. If it specifically says GPT, it means OpenAI's version in particular.

When you're choosing between AI tools or reading their marketing, that difference tells you who actually built the engine under the hood.