Anthropic Token Cost Calculator

Paste a message, attach files, pick a model — see the bill before you send.

Model Cache mode (input pricing) Anthropic API key Sent only via the X-Anthropic-Key header to this server, then forwarded to Anthropic. Never written to disk on the server. Held in memory by default; tick "Remember in this tab" to persist in sessionStorage (cleared when the tab closes). Remember in this tab (sessionStorage only) System prompt (optional) User message Attachments (.pdf, .txt, .csv — 10 MB each, 25 MB total) Expected output tokens: 1024

How do I estimate output tokens?

Output tokens are what Claude generates back. Pay attention — output is typically 5× the price of input.

Short reply (yes/no, classification, one sentence): ~20–80 tokens
Paragraph answer (definition, summary): ~150–400 tokens
Long answer (essay, structured report): ~800–2,000 tokens
Code generation (function, small file): ~500–1,500 tokens
Document rewrite (full rewrite of input): roughly the input length

Rule of thumb: 1 token ≈ 4 characters ≈ 0.75 words in English. Set the slider to your expected ceiling, not your average.

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