What is a token?

Models don't read words. They read tokens — short chunks of text that get turned into numbers before anything else happens.

A token is often a whole common word (the), sometimes part of a word (un + happiness), sometimes a single character or symbol. As a rough rule, one token is about three quarters of an English word, or around four characters.

Why chunks instead of words?

Splitting on spaces feels obvious until a model meets a word it has never seen — a new product name, a typo, another language. Whole-word vocabularies would need millions of entries and still hit unknown words constantly.

Modern models split text into subwords instead. Common words keep their own token; rare words fall back to familiar pieces. The model never gets stuck: anything can be spelled out from parts it already knows.

Type anything above. The colors are approximate — every model slices text slightly differently — but the count and the cost use the same math as the calculator.

Why tokens decide your bill

Providers charge per million tokens, with input and output priced separately. Output almost always costs more: looking up an input token is cheap, generating each output token means running the whole model again. Think of it like a factory — unloading raw materials is cheap, manufacturing each new item is not.

So two things decide every invoice: how many tokens your text becomes, and each token's price. Change either and the number moves.

Quirks worth knowing

Because models see chunks and not letters, they can be oddly bad at letter-level questions — like counting the r's in "strawberry". They never see the letters, only the chunks. Emoji, code, and non-English text also split less efficiently, which means they cost more per idea than plain English.

What to do with this

• Keep prompts tight: every token is billed.
• Prefer one precise word over three vague ones.
• Price the prompt before shipping it — open the calculator and paste the exact text your app sends.
• Check where each rate came from on Sources, and how the math works in Methodology.