Claude Sonnet 5's advertised API rate needs to be read alongside its changed text accounting. Anthropic's announcement and August 10 pricing update set permanent rates of $2 per million input tokenThe chunk of text a model reads and writes in — roughly three-quarters of a word — and the unit AI usage is billed in.Full definition → and $10 per million output tokens, replacing a planned increase. The same page says its updated tokenizer, which divides text into model units, can count roughly 1.0 to 1.35 times as many input tokens for the same content. Estimating the cost of an existing workload therefore requires both the new rate and its token count under the new model.
Terms in this piece · Glossary
token — The chunk of text a model reads and writes in — roughly three-quarters of a word — and the unit AI usage is billed in.
