AI tokens and context windows explained

A token is the unit AI companies count and charge for: a whole word, part of a word, or a punctuation mark. In English, 100 tokens is roughly 75 words on ChatGPT and Gemini.

The same text doesn't produce the same count everywhere. Current Claude models split English into roughly 35% more tokens than ChatGPT does, so two models with the same price per token can still cost different amounts for the same job.