Claude Fable 5.1
Pricing & Specs
Anthropic · $10 input / $50 output per 1M tokens · 1M context window
The per-token price never tells the full story. A typical task (1K input + 500 output tokens) on Claude Fable 5.1 costs about $0.0350, roughly $35.00 per 1,000 runs. But if it needs 3x the tokens of a cheaper model to match quality on YOUR task, the economics flip. The only way to know is to benchmark it on your actual workload.
Claude Fable 5.1 API Pricing
| Tokens | Price |
|---|---|
| Input | $10 / 1M tokens |
| Output | $50 / 1M tokens |
| Cached input | $0.25 / 1M tokens |
50% discount available for batch API requests. Cache writes: $12.50/MTok (5min), $20/MTok (1hr). Cache reads: $0.25/MTok (a quarter of Fable 5 cache read cost).
What that means in practice
Claude Fable 5.1 Specs
| Spec | Value |
|---|---|
| Context window | 1M tokens |
| Max output tokens | 128K tokens |
| Input modalities | text, image |
| Output modalities | text |
| Knowledge cutoff | Jun 2026 |
| Reasoning model | Yes |
| Tool / function calling | Yes |
| JSON mode | Yes |
| Streaming | Yes |
| Prompt caching | Yes |
| Batch API | Yes |
Notes
Released September 1, 2026. Adaptive thinking always on, default effort high. Breaking vs Fable 5: forced tool use returns error; thinking blocks tied to producing model; editing earlier turns invalidates thinking blocks.
FAQ
How much does Claude Fable 5.1 cost?
Claude Fable 5.1 costs $10 per 1M input tokens and $50 per 1M output tokens ($0.25 per 1M cached input tokens).
What is Claude Fable 5.1's context window?
Claude Fable 5.1 has a 1M-token context window. Maximum output is 128K tokens.
Can I test Claude Fable 5.1 on my own task?
Yes. OpenMark lets you benchmark Claude Fable 5.1 against 100+ models on your own task with real API calls, with no API keys needed, free tier available.
Is Claude Fable 5.1 the right model for YOUR task?
Pricing tables can't answer that. Benchmark it against 100+ models
on your actual workload: real API calls, real costs. Free tier available.