Claude Fable 5 Explained: Price, Specs and Parameters
In short: Claude Fable 5 is Anthropic's highest-capability model line, made generally available on June 9, 2026. Through the API it costs $10 per million input tokens and $50 per million output tokens, with a 1-million-token context window, and Anthropic does not publish its parameter count. Its successor, Claude Fable 5.1, was released on September 1, 2026 at the same $10/$50 price.
What is Claude Fable 5?
Claude Fable 5 is the largest and most capable model in Anthropic's Claude 5 lineup, built for the hardest reasoning and long, multi-step work. It sits above Opus, Sonnet and Haiku in Anthropic's range. Anthropic describes the current Fable model, Fable 5.1, as "for demanding reasoning and long-horizon agentic work" on its models overview.
"Long-horizon agentic work" means tasks where the model works on its own for a long time - planning, using tools, checking results and continuing - rather than answering a single question.
The trade-off is speed and price. Anthropic's overview rates the Fable line's comparative latency as "Slower", the slowest of its current models, and it is the most expensive per token.
When was Claude Fable 5 released?
Claude Fable 5 became generally available on June 9, 2026. Anthropic released the invitation-only Claude Mythos 5 alongside it. Claude Fable 5.1 followed on September 1, 2026.
How much does Claude Fable 5 cost?
Through Anthropic's API, Claude Fable 5 costs $10 per million input tokens and $50 per million output tokens, according to Anthropic's pricing page. A token is roughly three-quarters of an English word, so a million tokens is about 750,000 words.
| Item | Price per million tokens |
|---|---|
| Input | $10 |
| Output | $50 |
| Prompt caching - 5-minute write | $12.50 |
| Prompt caching - 1-hour write | $20 |
| Prompt caching - cache hit | $1 |
Claude Fable 5.1 has the same $10/$50 base price, but a lower cache-hit price of $0.25 per million tokens.
What does that mean in practice? A request that sends 10,000 tokens (about 7,500 words) and gets back 2,000 tokens (about 1,500 words) costs $0.10 for the input plus $0.10 for the output: $0.20 in total.
In the Claude apps, Anthropic's plans are Free ($0), Pro ($20 a month, or $17 a month billed annually) and Max (from $100 a month). The pricing page does not list which plan includes which specific model.
How many parameters does Claude Fable 5 have?
Anthropic does not publish the parameter count of Claude Fable 5, or of any current Claude model. Parameters are the learned numbers inside a model; for what they are and why labs keep them private, see how LLMs work. Any figure for Fable 5's size found elsewhere is an estimate, not an Anthropic number.
What are Claude Fable 5's specs?
- Context window: 1 million tokens.
- Maximum output: 128,000 tokens.
- Input: text and images; output: text.
- Thinking: always-on adaptive thinking - the model always reasons before answering and this cannot be turned off.
- Latency: rated "Slower" by Anthropic, the slowest current Claude line.
How does Claude Fable 5 rank?
On LMArena's text leaderboard, which ranks models by blind human votes, Fable 5 has 1504 Elo (rank 6, high effort) and Fable 5.1 has 1504 Elo (rank 5, max effort). The live order is on our benchmarks table.
Claude Fable 5 vs other Claude models
| Model | Input / output price (per 1M tokens) | Latency (Anthropic) |
|---|---|---|
| Claude Fable 5.1 | $10 / $50 | Slower |
| Claude Fable 5 | $10 / $50 | Slower |
| Claude Opus 5.5 | $4 / $20 | Moderate |
| Claude Sonnet 5.5 | $2 / $10 | Fast |
| Claude Haiku 5.5 | from $0.10 / from $0.50 | Fastest |
Prices from Anthropic's pricing page; latency ratings from its models overview.
Related
Frequently asked questions
What is Claude Fable 5?+
Claude Fable 5 is Anthropic's highest-capability Claude model line, designed for demanding reasoning and long, multi-step agentic tasks. It is slower and more expensive than Claude Opus, Sonnet and Haiku.
How much does Claude Fable 5 cost?+
Through Anthropic's API, Claude Fable 5 costs $10 per million input tokens and $50 per million output tokens, with cached input at $1 per million. In the Claude apps, Anthropic's plans are Free, Pro at $20 a month and Max from $100 a month.
How many parameters are in Claude Fable 5?+
Anthropic has not published the parameter count for Claude Fable 5 or its other current models, so there is no official figure.
When was Claude Fable 5 released?+
Claude Fable 5 became generally available on June 9, 2026. Its successor, Claude Fable 5.1, was released on September 1, 2026.
What is the difference between Claude Fable 5 and Fable 5.1?+
Fable 5.1 is the newer version. Both cost $10 per million input tokens and $50 per million output tokens, but Fable 5.1's cache-hit price is $0.25 per million tokens against Fable 5's $1.
What is the difference between Claude Fable and Claude Opus?+
Fable is Anthropic's highest-capability line and Opus sits just below it. Fable costs more, $10 and $50 per million input and output tokens against Opus 5.5's $4 and $20, and Anthropic rates it slower.
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