Claude Fable 5.1 vs Claude Sonnet 4.5
Benchmark Performance
Available Benchmarks
| Benchmark | Claude Fable 5.1 | Claude Sonnet 4.5 |
|---|---|---|
| ARC-AGI-1verified-v1-2aa739d957fc · verified_score · leader | 97.50100% of row best · percent · Claude Fable 5.1 (Max) | 63.6765% of row best · percent · Claude Sonnet 4.5 (Thinking 32K) |
| ARC-AGI-2verified-v2-b5cb5ec6e8c7 · verified_score · leader | 90.00100% of row best · percent · Claude Fable 5.1 (XHigh) | 13.6115% of row best · percent · Claude Sonnet 4.5 (Thinking 32K) |
| Overall ResultCounted from the protocol-matched rows above | 2 benchmark winsOverall lead | 0 benchmark wins |
Third-party benchmark Only like-for-like primary-publisher results are shown; raw scores, relative scores, configuration, and token spend remain visible.
Technical Differences
Side-by-Side Facts
| Field | Claude Fable 5.1 | Claude Sonnet 4.5 |
|---|---|---|
| Developer | Anthropic | Anthropic |
| Family | Claude 5 1 | Claude 4 |
| Model | Claude Fable 5.1 | Claude Sonnet 4.5 |
| Version | Claude Fable 5.1 | Claude Sonnet 4.5 |
| Lifecycle | active | active |
| Released | 2026-09-01 | 2025-09-29 |
| Knowledge cutoff | 2026-06-01 | 2025-01-01 |
| Input modalities | Text, Image | Text, Image |
| Output modalities | Text | Text |
| Context window | 1,000K | 200K |
| Total parameters | Unknown | Unknown |
| Active parameters | Unknown | Unknown |
| License | Unknown | Unknown |
| Open weights | No | No |
| API available | Yes | Yes |
| Self-hostable | No | No |
| Provider access | Anthropic (Standard) | Anthropic (Standard) |
| Capabilities | chat, generation, reasoning, tools | chat, generation, reasoning, structured_outputs, tools |
15 comparable fields · 7 material differences · Pair passes the primary-source comparison gate
Claude Fable 5.1 Capabilities
Claude Sonnet 4.5 Capabilities
Internal Comparison Graph
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|---|---|---|---|
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Claude Fable 5.1Anthropic | vs |  Mistral Large 3Mistral AI | cross-developer peersimage, text |
Primary Evidence
Sources and Freshness
Questions
Claude Fable 5.1 vs Claude Sonnet 4.5 FAQs
Is Claude Fable 5.1 or Claude Sonnet 4.5 better for coding?+
This comparison does not currently contain a protocol-matched coding benchmark for both Claude Fable 5.1 and Claude Sonnet 4.5, so Model Markets cannot name a coding leader from pricing, context size, or capability labels alone.
Which is cheaper, Claude Fable 5.1 or Claude Sonnet 4.5?+
Claude Fable 5.1 is $10.00 and Claude Sonnet 4.5 is $3.00 per million tokens, so Claude Sonnet 4.5 is cheaper on this metric. Claude Fable 5.1 is $50.00 and Claude Sonnet 4.5 is $15.00 per million tokens, so Claude Sonnet 4.5 is cheaper on this metric.
Which has a larger context window, Claude Fable 5.1 or Claude Sonnet 4.5?+
Claude Fable 5.1 has the larger sourced context window. Claude Fable 5.1 supports 1,000K and Claude Sonnet 4.5 supports 200K.
Which performs better in benchmarks, Claude Fable 5.1 or Claude Sonnet 4.5?+
There is no overall benchmark winner: An overall winner requires at least two decisive benchmarks from at least two original publishers.
Can Claude Fable 5.1 or Claude Sonnet 4.5 be self-hosted?+
Both models have the same recorded self-hosting status: unsupported. Claude Fable 5.1 is not marked open weight; Claude Sonnet 4.5 is not marked open weight.
Can Claude Fable 5.1 and Claude Sonnet 4.5 understand images?+
Claude Fable 5.1 is documented with image input; Claude Sonnet 4.5 is documented with image input. This reflects supported input modalities, not vision quality.
Which can generate longer answers, Claude Fable 5.1 or Claude Sonnet 4.5?+
Claude Fable 5.1 has the larger sourced maximum output: Claude Fable 5.1 supports 128K and Claude Sonnet 4.5 supports 64K output tokens.
Do Claude Fable 5.1 and Claude Sonnet 4.5 support reasoning and tool use?+
Claude Fable 5.1: reasoning, tool calling, and image input. Claude Sonnet 4.5: reasoning, tool calling, and image input. Feature support does not establish relative quality.
Which is available from more inference providers, Claude Fable 5.1 or Claude Sonnet 4.5?+
Claude Fable 5.1 has 1 sourced provider route; Claude Sonnet 4.5 has 1, a tie.
Which offers better value, Claude Fable 5.1 or Claude Sonnet 4.5?+
There is no universal value winner. Compare the input and output prices above with the matched benchmark result for your workload: cheaper tokens can be offset by different quality, token usage, latency, or provider availability.