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Claude Fable 5.1: price and specs
Claude Fable 5.1 is the top Claude model open to everyone, released on 1 September 2026. It costs $10.00 per million input tokens and $50.00 per million output tokens, 2.5 times the price of Claude Opus 5.5. Anthropic itself suggests starting with Opus 5.5 and moving up to Fable 5.1 only when a task needs it.
Checked October 14, 2026 against Anthropic’s Claude Fable 5.1 page and pricing page
Fable 5.1 next to the other Claude models
| Model | Input / output | Cached input | Speed | Thinking | Default effort | What Anthropic says it is for |
|---|---|---|---|---|---|---|
| Claude Fable 5.1 | $10.00 / $50.00 | $0.25 | Slower | Adaptive, always on | High | Demanding reasoning and long-horizon agentic work |
| Claude Opus 5.5 | $4.00 / $20.00 | $0.20 | Moderate | Adaptive, always on | Medium | Long-running agentic coding and knowledge work |
| Claude Sonnet 5.5 | $2.00 / $10.00 | $0.10 | Fast | Adaptive | High | The best combination of speed and intelligence |
| Claude Haiku 5.5 | $0.10 / $0.50 | $0.01 | Fastest | Adaptive | Medium | High-volume, latency-sensitive tasks |
Claude Haiku 5.5 costs more on prompts over 100,000 tokens. All four models have a 1M-token context window and 128,000-token output limit, and a reliable knowledge cutoff of June 2026.
What one request costs
Example: a request with 20,000 tokens in and 2,000 out. In the second row, 18,000 of those input tokens are read from the prompt cache, as in a long conversation or a fixed set of instructions.
| Fable 5.1 | Opus 5.5 | Sonnet 5.5 | |
|---|---|---|---|
| No caching | $0.30 | $0.12 | $0.06 |
| Most input cached | $0.1245 | $0.0516 | $0.0258 |
Output tokens make up most of the bill, so caching narrows the gap only a little. Fable 5.1 thinks at high effort by default, and thinking counts as output, so real requests can use more output tokens than the same task on Opus 5.5.
Fable 5.1 vs Opus 5.5 for your use
Models
- Turn on JavaScript to see the costs. The price tables below work without it.
What changed from Claude Fable 5
Fable 5.1 keeps Fable 5’s input and output prices. Cached input now costs a quarter as much: $0.25 per million tokens, down from $1.00. Anthropic says Fable 5.1 is stronger at long agentic coding, multistep research, and document, spreadsheet and slide work.
Developers moving from Fable 5 should read Anthropic’s what’s new page: it lists three breaking changes, including that forced tool use now returns an error.
Fable 5.1 and Claude Mythos 5.1
Claude Mythos 5.1 shares Fable 5.1’s specifications and prices, but Anthropic offers it only to organizations verified through its programs, such as the Cyber Verification Program. Fable 5.1 is the version anyone can use.
Where you can use it
Fable 5.1 is on Anthropic’s Claude API, Amazon Bedrock, Google Cloud, Microsoft Foundry and Claude Platform on AWS. On Bedrock’s global endpoint the per-token prices are the same as Anthropic’s, but Bedrock lists no batch discount for it. See AWS Bedrock pricing. Anthropic plans to keep it available until at least 1 September 2027.