Token Economics

Tokenizer Drift

Different model versions can count the same text as a different number of tokens, which changes the bill.

Definition

Token counts for the same text change between tokenizer versions. The tokenizer introduced with Claude Opus 4.7 produces about 30% more tokens for the same text than earlier Claude tokenizers, so budgets and cost estimates need re-measuring after a model switch.

Example

A prompt that counted 10,000 tokens on Claude Opus 4.6 counts about 13,000 on Opus 4.7, so the same request costs about 30% more.

See it in actionToken cost calculator