Model tracker / Anthropic
Claude Mythos 5.1
Claude Mythos 5.1 is a frontier model from Anthropic, released 1 September 2026. At Anthropic it costs $10.00 per million input tokens and $50.00 per million output tokens, with a 1M-token context window.
- Made by
- Anthropic
- Released
- 2026-09-01
- Status
- Generally available
- Tier
- Frontier
- Weights
- Closed
- Context window
- 1,000,000 tokens
- Max output
- 128,000 tokens
- Input
- text, image
- API id
claude-mythos-5-1
Claude Mythos 5.1 price at Anthropic
US dollars per million tokens. Blended is 3 input tokens for every output token, one number to compare on.
| Provider | Input | Output | Cached input | Blended | Batch | Checked |
|---|---|---|---|---|---|---|
| Anthropic · maker | $10.00 | $50.00 | $0.25 | $20.00 | 50% off | 2026-10-17 |
- Anthropic: Available only to organizations verified through Anthropic's verification programs, such as the Cyber Verification Program; same specifications and pricing as Claude Fable 5.1. Cache writes $12.50 (5 min) or $20 (1 h).
Models like Claude Mythos 5.1
Other frontier models closest in price, at each maker's own price or the cheapest provider.
| Model | Input | Output | Context | Weights |
|---|---|---|---|---|
| Claude Mythos 5.1 | $10.00 | $50.00 | 1M | Closed |
| Claude Fable 5.1 Anthropic | $10.00 | $50.00 | 1M | Closed |
| GPT-6 Astra OpenAI | $10.00 | $50.00 | 1.1M | Closed |
| Claude Opus 5.5 Anthropic | $4.00 | $20.00 | 1M | Closed |
| Muse Wonder Meta | $4.00 | $20.00 | 1M | Closed |
| Gemini 4 Argon Google | $2.00 | $10.00 | 1M | Closed |
Compare them all in the model tracker →
Claude Mythos 5.1 FAQ
How much does Claude Mythos 5.1 cost?
Claude Mythos 5.1 costs $10.00 per million input tokens and $50.00 per million output tokens at Anthropic, and $0.25 per million cached input tokens, with 50% off for batch requests. Prices are list prices in US dollars, last checked 17 October 2026.
What is Claude Mythos 5.1's context window?
Claude Mythos 5.1 takes up to 1,000,000 tokens in one request and writes up to 128,000 tokens in one response.
Is Claude Mythos 5.1 open weight?
No. Claude Mythos 5.1 is only available through Anthropic's API; Anthropic doesn't publish the weights.
Where can I use Claude Mythos 5.1?
Claude Mythos 5.1 is available from Anthropic. At Anthropic, call it as claude-mythos-5-1.