Tokens vs Characters

Characters count letters, numbers, punctuation, and spaces. Tokens are the chunks of text that the model uses internally. They are related, but they are not the same thing.

Why this difference matters

MetricWhat it measuresWhy it matters
CharactersLiteral text lengthUseful for rough size checks and UI limits
TokensModel-processed text unitsUsually the main driver of API cost and context usage

Practical takeaway

Characters can help you estimate. Tokens usually determine billing. That is why a prompt that looks short in plain text can still use more tokens than expected.

How to stay safe