Claude Fable 5.1 vs Claude Sonnet 5
At a Glance
| Compare | Claude Fable 5.1Anthropic | Claude Sonnet 5Anthropic |
|---|---|---|
| Intelligence, Cost, and Efficiency | ||
| IntelligenceHigher is better · MM Intelligence v4.4 | #2 of 5799.0 score · 3/3 sources · complete | #18 of 5763.1 score · 2/3 sources · provisional · missing ARC-AGI-2 · full-core range 42.1–75.4 |
| CostLower is better · Published-token output estimate | #27 of 27$0.824 per LiveBench case | #20 of 27$0.194 per LiveBench case |
| EfficiencyHigher is better · MM Efficiency v1.9 | #14 of 2749.5 score · 3/3 sources · complete | #21 of 2743.5 score · 2/3 sources · provisional · missing ARC-AGI-2 · full-core range 33.0–49.6 |
| Pricing and Limits | ||
| Input priceFrom · USD / 1M tokens | $10.00Anthropic ↗ · Sep 3, 2026 | $2.00Anthropic ↗ · Sep 3, 2026 |
| Output priceFrom · USD / 1M tokens | $50.00Anthropic ↗ · Sep 3, 2026 | $10.00Anthropic ↗ · Sep 3, 2026 |
| Context windowMaximum documented tokens | 1,000K | 1,000K |
| Model facts checked | Sep 2, 2026View model evidence → | Aug 28, 2026View model evidence → |
Token prices are the lowest available sourced USD rates; input and output may use different providers. Cost ranking estimates output spend on LiveBench, not a full request bill. Ranking methodology →
Available Benchmarks
| Benchmark | Claude Fable 5.1 | Claude Sonnet 5 |
|---|---|---|
| LMArena Agent Arenaagent-2026-10-16-a64ca3b12b6e · outcome_score · leader | 14.03100% of row best · score · Claude Fable 5.1 (Max); 95% CI [12.03932907, 16.02502568]; sessions 16374; observations 1913479; rank 3 | 4.5892% of row best · score · Claude Sonnet 5 (High); 95% CI [2.88280252, 6.28024714]; sessions 33276; observations 3570560; rank 12 |
| LMArena Document Arenadocument-2026-09-13-a64ca3b12b6e · arena_rating · leader | 1,512.58100% of row best · rating · claude-fable-5.1-max; 95% CI [1497.40364732, 1527.76498981]; votes 1403; rank 2 | 1,466.1497% of row best · rating · claude-sonnet-5-high; 95% CI [1458.49407458, 1473.77896309]; votes 7411; rank 17 |
| LMArena Vision Arenavision-2026-10-09-a64ca3b12b6e · arena_rating · leader | 1,318.24100% of row best · rating · claude-fable-5.1-max; 95% CI [1308.61778049, 1327.86146111]; votes 4648; rank 4 | 1,273.9297% of row best · rating · claude-sonnet-5-high; 95% CI [1267.02186706, 1280.81063637]; votes 13503; rank 41 |
| LiveBench2026-06-25-90f8d44da965 · overall · leader | 86.82100% of row best · percent · claude-fable-5-1-max-effort · 16,470 output tokens / case | 80.0192% of row best · percent · claude-sonnet-5-xhigh-effort · 19,428 output tokens / case |
| ToneBench2026-10-17-10-task-e9c76358afb2 · overall_score · unverified | 84.53100% of row best · points · Claude Fable 5.1 (max effort) · 68,653 output tokens / case | 79.2194% of row best · points · Claude Sonnet 5 (max effort) · 66,953 output tokens / case |
| Overall ResultCounted from the protocol-matched rows above | 4 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.
Quality Versus Estimated Output Cost
Side-by-Side Facts
| Field | Claude Fable 5.1 | Claude Sonnet 5 |
|---|---|---|
| Developer | Anthropic | Anthropic |
| Family | Claude 5 1 | Claude 5 |
| Model | Claude Fable 5.1 | Claude Sonnet 5 |
| Version | Claude Fable 5.1 | Claude Sonnet 5 |
| Lifecycle | active | active |
| Released | 2026-09-01 | 2026-06-30 |
| Knowledge cutoff | 2026-06-01 | Unknown |
| Input modalities | Text, Image | Text, Image |
| Output modalities | Text | Text |
| Context window | 1,000K | 1,000K |
| 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), Deepinfra (Standard), Openrouter (Standard) |
| Capabilities | chat, generation, reasoning, tools | chat, generation, reasoning, tools |
Claude Fable 5.1 Capabilities
Claude Sonnet 5 Capabilities
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Primary Evidence
Sources and Freshness
Questions
Claude Fable 5.1 vs Claude Sonnet 5 FAQs
Is Claude Fable 5.1 or Claude Sonnet 5 better for coding?+
This comparison does not currently contain a protocol-matched coding benchmark for both Claude Fable 5.1 and Claude Sonnet 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 5?+
Claude Fable 5.1 is $10.00 and Claude Sonnet 5 is $2.00 per million tokens, so Claude Sonnet 5 is cheaper on this metric. Claude Fable 5.1 is $50.00 and Claude Sonnet 5 is $10.00 per million tokens, so Claude Sonnet 5 is cheaper on this metric.
Which has a larger context window, Claude Fable 5.1 or Claude Sonnet 5?+
Both models have the same sourced context window: 1,000,000 tokens each.
Which performs better in benchmarks, Claude Fable 5.1 or Claude Sonnet 5?+
Claude Fable 5.1 leads the current overall benchmark count. The result uses 4 protocol-matched benchmarks from 2 publishers; it is not a universal quality score.
Can Claude Fable 5.1 or Claude Sonnet 5 be self-hosted?+
Both models have the same sourced self-hosting status: unsupported. Claude Fable 5.1 is not marked open weight; Claude Sonnet 5 is not marked open weight.
Can Claude Fable 5.1 and Claude Sonnet 5 understand images?+
Claude Fable 5.1 is documented with image input; Claude Sonnet 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 5?+
Both models have the same sourced maximum output: 128,000 tokens each.
Do Claude Fable 5.1 and Claude Sonnet 5 support reasoning and tool use?+
Claude Fable 5.1: reasoning, tool calling, and image input. Claude Sonnet 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 5?+
Claude Fable 5.1 has 1 sourced provider route; Claude Sonnet 5 has 3, so Claude Sonnet 5 has broader tracked availability.
Which offers better value, Claude Fable 5.1 or Claude Sonnet 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.