Token

What it means. A token is a small chunk of text an AI model reads and writes, usually a few characters or part of a word. Models do not process whole sentences at once. They process sequences of tokens.

Why it matters. Cost, speed, and limits are all measured in tokens, not words. Longer prompts and longer answers use more tokens, which means more money and more time, and they can run into hard limits.

What beginners often misunderstand. A token is not the same as a word. As a rough guide, 100 tokens is about 75 words of English. Spaces and punctuation count too.

How it shows up in real projects. Token limits decide how much background information you can send, how long a reply can be, and how much each AI request costs. Features that ignore token budgets tend to get expensive or get cut off mid-answer.