Token
1 min read · Reviewed 17 Oct 2026
In short
The small chunks of text an AI reads and writes in.
In plain English
Models don't read letters or whole words — they read tokens, which are word-fragments. A common word is usually one token; a longer or unusual one splits into several. Roughly, 1,000 tokens is about 750 English words.
A real example
"Reading" might be one token. An unusual product name might be four. That is why pasting a long document uses up far more of the context window than the page count suggests.
Why it matters
Tokens are the unit that limits and prices AI. Context windows are measured in them, and API bills are calculated from them — so knowing roughly how many you're using explains both the cost and the forgetting.
