Latest release
Choose Claude Mythos 5.1
Claude Mythos 5.1 is the newer release (September 2026, against April 2026 for Claude Mythos Preview).
Claude Mythos 5.1 vs Claude Mythos Preview: price, context and capabilities
Choose Claude Mythos 5.1 for the latest release; on the other points the two are level or the data is missing.
In short
- A price comparison is not possible: one of them has no comparable published price.
- Claude Mythos 5.1 is the newer model (September 2026, against April 2026).
- Only Claude Mythos 5.1 offers prompt caching.
Which should you choose?
Each answer below comes straight from the published prices, specifications and independent benchmark results.
Specifications side by side
| Claude Mythos 5.1 | Claude Mythos Preview | |
|---|---|---|
| Provider | Anthropic | Anthropic |
| Category | Language models | Language models |
| Status | Generally available · Limited access | Deprecated · Limited access |
| Headline price | $20.00 / 1M tokens | No data |
| Input | $10.00 / 1M tokens | No data |
| Output | $50.00 / 1M tokens | No data |
| Cached input | $0.25 / 1M tokens | No data |
| Context window | 1M | No data |
| Max output | 128k | No data |
| Released | September 2026 | April 2026 |
| Knowledge cutoff | No data | No data |
| Licence | Proprietary | Proprietary |
| Capabilities | Vision, Reasoning, Tool calling, Structured output, Prompt caching, Batch API | Vision, Reasoning, Tool calling, Structured output, Batch API |
| API model id | claude-mythos-5-1 | claude-mythos-preview |
Frequently asked questions
Should I choose Claude Mythos 5.1 or Claude Mythos Preview?
Choose Claude Mythos 5.1 for the latest release; on the other points the two are level or the data is missing.
Which is cheaper, Claude Mythos 5.1 or Claude Mythos Preview?
A price comparison is not possible: one of them has no comparable published price.
What is the difference between Claude Mythos 5.1 and Claude Mythos Preview?
Claude Mythos 5.1 is made by Anthropic and Claude Mythos Preview by Anthropic. A price comparison is not possible: one of them has no comparable published price. Claude Mythos 5.1 is the newer model (September 2026, against April 2026). Only Claude Mythos 5.1 offers prompt caching.
Which is newer, Claude Mythos 5.1 or Claude Mythos Preview?
Claude Mythos 5.1 was released on September 2026 and Claude Mythos Preview on April 2026.