# Model

> The trained system that actually produces the answers. Claude comes in several models that trade speed for power.

**Category:** Core concept, Claude

**A model is the thing you are really talking to**: a system trained on huge amounts of text that generates responses. Different models suit different jobs, so Claude offers a few, from **fast and light to slow and powerful**.

Picking the right one is a small but useful skill: **reach for the everyday model for most work**, and the heavyweight only when a task is *genuinely* hard.

## At work

Drafting a quick reply? The fast model is plenty and you barely wait. Working through a knotty contract? Switch to the heavyweight and let it take its time. Same chat box, different engine.

## Often confused with

The app or chatbot. The window you type into is the wrapper; the model is the trained engine inside it that actually writes the answer.

## Related terms

- Generative AI

## See it in a lesson

[Models, thinking, and web access](/en/learn/getting-started-with-claude/models-thinking-and-web-access)

## Further reading

- [Claude models overview (Anthropic)](https://docs.claude.com/en/docs/about-claude/models/overview): Anthropic's own rundown of the Claude models and what each is for.
- [Large language model (Wikipedia)](https://en.wikipedia.org/wiki/Large_language_model): Background on the kind of model behind chat tools.
- [What are large language models? (IBM)](https://www.ibm.com/think/topics/large-language-models): A plain explainer of how these models are built and used.

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Last updated: 24/07/2026  
Source: Rollo Academy glossary