Claude Code session cost calculator
Drop one or more .jsonl session files from ~/.claude/projects/<your-project>/. The page reads the usage block of every assistant message and prices it at Anthropic's list prices. Nothing leaves your machine: there is no upload, no server, no analytics on this page beyond the site's page-view counter.
Drop session files here or
Windows: C:\Users\<you>\.claude\projects\ · macOS/Linux: ~/.claude/projects/
Prices used (USD per million tokens, list prices as of September 2026; edit if yours differ)
| Model | Input | Output | Cache read | Cache write |
|---|
Cache write for Fable is our assumption (1.25x input); the published table lists input, output and cache read. Unknown models fall back to the Fable row.
How to read the numbers
Four counters, four prices. Output tokens are what the model wrote; they are the most expensive per token. Cache read is context the model re-read from the prompt cache on each call; cheap per token, huge in volume on long sessions. Cache write is context stored into the cache for the first time. Input is uncached prompt tokens, usually tiny in Claude Code.
A session that costs a lot with a modest output count is a long session: every call re-reads everything before it. The fix is structural, not a model swap: shorter sessions, one task each, state carried in files rather than in the conversation. The guide on token cost has the script version of this page and the reasoning; what Claude Code reads on every session has the habits.
Privacy
The files are parsed by the JavaScript on this page and never sent anywhere. You can verify that with the browser's network panel, or by reading the page source: there is no fetch call in it.