Token: complete definition in AI for SMEs

A token is the basic unit a language model processes: a piece of text (often part of a word, sometimes a whole word, sometimes punctuation) that the model analyzes and generates. Everything you send to and receive from an AI breaks down into tokens — and tokens are also the billing unit of AI APIs: you pay per input token plus per output token.

Why it matters for your budget

Understanding tokens means understanding the real cost of AI:

• a long text or a large document injected in every request costs on each call — hence reducing redundant contexts;
• RAG systems split your documents into chunks sized to limit tokens;
• asking AI to reword an already-written text burns unnecessary tokens.

Best practice

A good AI architect optimizes tokens to control cost: compact prompts, relevant contexts, caching. It is one of the most concrete profitability levers of fractional AI leadership — AI becomes a managed cost line, not a month-end surprise.