Claude Fable 5 — Specifications
| Developer | Anthropic |
|---|---|
| Type | LLM (frontier reasoning) |
| Modality | Text, Vision → Text |
| Parameters | Undisclosed |
| Context window | 1M |
| Max output | 128K |
| License | Proprietary |
| Open weights | No |
| Released | 2026 |
| Input price | $10.00 /1M |
| Output price | $50.00 /1M |
| API providers | Anthropic, AWS |
What is Claude Fable 5?
Claude Fable 5 is Anthropic’s most capable widely released model, positioned above the
Opus tier and priced accordingly at $10 in / $50 out per million tokens. Thinking is always
on — there is no non-reasoning mode to fall back to — which is what makes it strong on
long-horizon agentic work and what makes it expensive on anything trivial. It pairs a
1M-token context window with a 128K maximum output, an unusually large generation budget
that matters when the task is producing a long artifact rather than answering a question.
The economics only work at the top of the difficulty curve. At $50 per million output
tokens, Fable 5 costs roughly five times Claude Opus 4.8 on the output side, so routing
ordinary requests to it burns budget for no measurable gain. The sensible pattern is a
router: Fable 5 for the small share of tasks where a wrong answer is expensive — multi-step
agents that run unattended, deep research, refactors across a large codebase — and a
Sonnet- or Haiku-tier model for everything else. If your workload is mostly retrieval and
summarisation, the price gap will dominate your bill long before capability does.
Claude Fable 5 pricing: API cost per 1M tokens
| Input (per 1M tokens) | $10.00 |
|---|---|
| Output (per 1M tokens) | $50.00 |
| Output/input ratio | 5× |
| Blended (4:1 in:out) | $18.00 per 1M tokens |
What Claude Fable 5 costs per month
Real monthly spend at a 4:1 input-to-output mix — the ratio a typical chat or RAG workload actually produces.
| Workload | Tokens / month | Cost / month |
|---|---|---|
| Side project | 1M in / 0.25M out | $23 |
| Small team | 20M in / 5M out | $450 |
| Production | 200M in / 50M out | $4,500 |
Run your own numbers in the AI API cost calculator.
Cheaper alternatives to Claude Fable 5
| Model | Blended $/1M | You save |
|---|---|---|
| Claude Opus 5 | $9.00 | 50% cheaper |
| GPT-5.6 Sol | $10.00 | 44% cheaper |
| Kimi K3 open | $5.40 | 70% cheaper |
Frequently asked questions
How much does Claude Fable 5 cost per 1M tokens?
Claude Fable 5 costs $10.00 per 1M input tokens and $50.00 per 1M output tokens. At a typical 4:1 input-to-output mix that blends to about $18.00 per 1M tokens.
How much does Claude Fable 5 cost per month?
A small-team workload of 20M input and 5M output tokens a month costs about $450 on Claude Fable 5. A side project (1M in / 0.25M out) costs roughly $22.50.
What is a cheaper alternative to Claude Fable 5?
Claude Opus 5 is the strongest cheaper option in our database at $9.00 per 1M blended — about 50% less than Claude Fable 5.
Can I run Claude Fable 5 locally?
No. Claude Fable 5 is a closed, API-only model — the weights are not released, so it cannot be self-hosted.
Why does Claude Fable 5 charge more for output than input?
Output tokens are generated one at a time and cannot be batched the way a prompt can, so they cost the provider more to serve. Claude Fable 5 charges 5× more for output, which is why prompt-heavy workloads are far cheaper to run than generation-heavy ones.
See every Claude model priced side by side: Claude API pricing.
Prices are the published list rates for the model's primary API and are reviewed as providers change them. Volume, batch and cached-input discounts are not included. Compare every model side by side in the AI models database or the LLM leaderboard.
