Historical model (legacy). The rates below are the last recorded rates, not a recommendation for a new deployment.
Claude Mythos 5.1 API Pricing
Claude Mythos 5.1 costs $10.00 per 1M input tokens and $50.00 per 1M output tokens. These rates were last verified on .
Moving off Claude Mythos 5.1?
Same token usage, 3:1 input:output, standard list rates · excludes cache, batch and fast mode. Not a quality or compatibility claim. Full calculator →
Claude Fable & Mythos pricing history
USD · units shown per rate · all Claude models →- Input: $8.00 / 1M tokensOutput: $40.00 / 1M tokensRate first observedLatestVerified 2026-11-12
- Input: $8.00 / 1M tokensOutput: $40.00 / 1M tokensRate first observedLatestVerified 2026-11-12
- Input: $10.00 / 1M tokensOutput: $50.00 / 1M tokensRate first observedAvailable · older versionVerified 2026-11-12
- Input: $10.00 / 1M tokensOutput: $50.00 / 1M tokensRate first observedAvailable · older versionVerified 2026-11-12
- Input: $10.00 / 1M tokensOutput: $50.00 / 1M tokensRate first observedAvailable · older versionVerified 2026-11-12
- Input: $10.00 / 1M tokensOutput: $50.00 / 1M tokensRate first observedAvailable · older versionVerified 2026-11-12
Newest first. Release dates describe the model, not when today's rates took effect. Observations show when we recorded rates, not launch pricing. Image and text token meters are separate; no fixed image-token savings mix is assumed. How we verify
Published rates and billing units
| Billing dimension | USD list price |
|---|---|
| Input / 1M tokens | $10.00 |
| Cached input / 1M tokens | $0.25 |
| Cache write / 1M tokens | $12.50 |
| Output / 1M tokens | $50.00 |
| Cache write (1 hour) / 1M tokens | $20.00 |
| Batch: Input / 1M tokens | $5.00 |
| Batch: Output / 1M tokens | $25.00 |
| Batch: Cached input / 1M tokens | $0.125 |
| Batch: Cache write / 1M tokens | $6.25 |
| Batch: Cache write (1 hour) / 1M tokens | $10.00 |
Verified 2026-11-12 · Official source · Pricing methodology. Taxes, optional services and account-specific discounts are not included.
Cost examples
These examples use published list prices only. They exclude taxes, enterprise discounts, minimum charges, retries, batch discounts, and provider-specific billing rules.
1M input + 1M output
$60.00
A direct per-million comparison against every other text model.
100K input + 25K output
$2.25
A compact chat, summarization, or analysis workload.
10M input + 2M output
$200.00
A monthly production estimate for heavier RAG or agent traffic.
75% cached input + 250K output
$15.19
Cached input is about 98% cheaper than standard input at list price.
Calculator for Claude Mythos 5.1
Enter your own input, output, and cached-token assumptions. This calculator is preloaded with only Claude Mythos 5.1, so the result stays focused on this model.
Input cost
$10.00
Output cost
$50.00
Total
$60.00
Price history
No list-price movement across 71 daily snapshots from 2026-09-02 to 2026-11-11.
When to use Claude Mythos 5.1
Good fit
- code generation, debugging, and agentic development work where output quality affects engineering time
- reasoning-heavy prompts, planning, analysis, and multi-step tool use
- long-document and repository-scale prompts where context window matters
Be careful with
- bulk summarization or simple classification where cheaper models can pass evaluation