Anthropic's newest tokenizer, Sonnet 5, generates approximately 30% more tokens from the same code compared to its previous version. For identical files, it produces 1.36 to 1.73 times the token count of GPT, with TypeScript resulting in the highest increase at 1.73 times.

Claude 4.7's new tokenizer uses 1.47 times more tokens than previous versions, exceeding the documentation estimate of 1.0–1.35x. This increase impacts the cost of processing content.