Claude Mythos 5.1 benchmarks, pricing and specs
Claude Mythos 5.1 is an Anthropic model released on September 1, 2026 that takes text and image input and produces text. It costs $10 per 1M input tokens and $50 per 1M output tokens.
- Per 1M input tokens
- $10
- Per 1M output tokens
- $50
Data verified October 11, 2026 · Dataset 2026-10-12
Key facts
- Provider
- Anthropic
- Model family
- Claude Mythos
- Release date
- September 1, 2026
- Status
- Current
- Access
- API only
- API model id
- Not reported
- Context window
- Not reported
- Max output
- Not reported
- Input
- text, image
- Output
- text
- Task families
- text, multimodal
- Declared capabilities
- reasoning
Claude Mythos 5.1 pricing
It is tied for the most expensive of 37 current text models priced per 1M input tokens.
Independent benchmark results
Scores come from independent evaluators that ran the model themselves, pinned to a dated snapshot. Rank is among current models in the same snapshot. Anthropic's own launch figures are listed under strengths with the publisher named, because they are not measured the same way.
No independent benchmark has published a result for Claude Mythos 5.1 yet. It is still compared below on price, context and capabilities.
Strengths, cautions and best uses
Strengths
- Shipped alongside Claude Fable 5.1 and listed at the same rates: $10 per million input, $50 per million output, and the same 0.025x cache-read multiplier ($0.25 per million)
- Carries the same reduced cache-read pricing as Fable 5.1, which no other Claude model has
Cautions
- Limited availability: access is restricted to organisations vetted through Anthropic’s Glasswing programme, so it cannot be assumed available for a general evaluation
- Anthropic’s public model comparison table does not list a context window or maximum output for Mythos 5.1, so both are recorded as unknown here rather than inferred from Fable 5.1
Best for
- Organisations already admitted to Anthropic’s limited-availability programme that need frontier capability at Fable 5.1 rates
Alternatives to Claude Mythos 5.1
The closest current textmodels by price. The cheapest model that scores as well or better is listed first; failing that, the cheapest one within 3% of the benchmark's scale.
Claude Fable 5
- Same price per 1M input tokens, $10
Claude Fable 5.1
- Same price per 1M input tokens, $10
GPT-6 Astra
- Same price per 1M input tokens, $10
- From OpenAI
GPT-5.5
- 50% cheaper per 1M input tokens, $5 vs $10
- From OpenAI
Compare Claude Mythos 5.1 with
Claude Mythos 5.1 FAQ
How much does Claude Mythos 5.1 cost?
Claude Mythos 5.1 costs $10 per 1M input tokens and $50 per 1M output tokens at the standard tier. It is tied for the most expensive of 37 current text models priced per 1M input tokens. Source: Anthropic, verified October 11, 2026.
Is Claude Mythos 5.1 open source or API only?
Claude Mythos 5.1 is available through Anthropic's API only; its weights are not published.
What are the best alternatives to Claude Mythos 5.1?
The closest current alternatives by price and measured performance are Claude Fable 5 (same price per 1M input tokens, $10), Claude Fable 5.1 (same price per 1M input tokens, $10), GPT-6 Astra (same price per 1M input tokens, $10) and GPT-5.5 (50% cheaper per 1M input tokens, $5 vs $10).
Sources
- Claude API pricing · Anthropic · official · verified October 11, 2026
- Claude Mythos limited availability · Anthropic · official · verified September 9, 2026
Cite this page
Van Data Team. "Claude Mythos 5.1 Benchmarks, Pricing and Specs." AI Model Benchmark Dataset 2026-10-12. https://vandatateam.com/ai-model-benchmarks/claude-mythos-5-1
Reuse the data: JSON · CSV · or explore every model in the AI model benchmark comparison.
Production evaluation
Deciding whether Claude Mythos 5.1 fits your workload?
Public benchmarks narrow the shortlist. We test the finalists on your own tasks, data and cost limits, then build the routing and review controls to run the winner in production.
- Evaluation cases and acceptance thresholds tied to real work
- Model routing, fallbacks and cost controls