How Much Does Claude Code Cost? Real Session Costs by Model

Claude Code is free to install, but users pay for the model it calls, either through a Claude subscription or per token on an API key. Median API-key session costs from OpenRouter data over the 30 days to October 18, 2026 were $0.31 for a 2–9-turn session and $1.39 for a 10–49-turn session on Claude Opus 5.5, versus $0.16 and $0.60 on Claude Sonnet 5.5. Most of the cost comes from Claude Code's own context written to the prompt cache on the first request and read back on later turns, so the article recommends Sonnet as default, Haiku for background jobs and sub-agents, shorter sessions, and a credit limit on the key.