Token
Also: tokens, token usage
A token is the basic unit Claude uses to read and write text — roughly three-quarters of a word. "Hello, how are you?" is about 6 tokens. Everything you send to Claude (your message, system prompt, uploaded documents) and everything Claude sends back counts as tokens. Tokens determine both your usage limits and your API costs. Understanding tokens helps you manage costs, stay within limits, and structure your prompts efficiently.
Articles
The unit everything in AI is priced and measured in
Tokens are how language models read and write text — and how every AI API charges you. Understanding them turns abstract pricing into something you can predict and control.
How to minimise your Claude token usage without sacrificing quality
Tokens are what you pay for. Here are the practical things you can do to use fewer of them — from how you prompt to which model you choose.