Claude Fable 5.1 vs Claude Sonnet 5: Specs & Benchmark Comparison
Claude Fable 5.1 and Claude Sonnet 5 both come from Anthropic, Claude Sonnet 5 was released in June 2026, and Claude Fable 5.1 followed 3 months later in September 2026.
The two models share 3 published benchmarks. Claude Fable 5.1 leads on 3 of them. The widest gaps are on Terminal-Bench 4.0, where Claude Fable 5.1 scores 55.8% against 12.4%; AutomationBench, where Claude Fable 5.1 scores 31.4% against 13.5%. Averaged across everything we track, Claude Fable 5.1 sits at 59.7% and Claude Sonnet 5 at 58.4%.
Claude Sonnet 5 is the cheaper API at $2 per million input tokens and $10 per million output tokens, roughly 5 times cheaper than Claude Fable 5.1 at $10 and $50. Both accept a context window of about 1M tokens. Both accept text and images as input.
| Characteristic | Claude Fable 5.1 | Claude Sonnet 5 |
|---|---|---|
| Company | Anthropic | Anthropic |
| Release Date | September 1, 2026 | June 30, 2026 |
| Parameters | — | — |
| Multimodal | Yes | Yes |
| Context (input) | 1.0M | 1.0M |
| Context (output) | 128K | 64K |
| Input Price / 1M | $10.00 | $2.00 |
| Output Price / 1M | $50.00 | $10.00 |
| Average Score | 59.7% | 58.4% |
| Benchmarks | ||
| Terminal-Bench 4.0 | 55.8% | 12.4% |
| AutomationBench | 31.4% | 13.5% |
| Humanity's Last Exam | 65.0% | 57.4% |
Visual Benchmark Comparison
Verdict
Both models show equal results — the choice depends on your specific use case.
Both models show comparable average scores: Claude Fable 5.1 — 0.6, Claude Sonnet 5 — 0.6.
Claude Sonnet 5 is 5.0x cheaper: input $2.00/1M vs $10.00/1M tokens.
Same context size: 1M tokens.
Claude Fable 5.1 is newer: released 9/1/2026 vs 6/30/2026.
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Frequently Asked Questions
Which is better for coding — Claude Fable 5.1 or Claude Sonnet 5?
Which model is cheaper — Claude Fable 5.1 or Claude Sonnet 5?
Which has a larger context window — Claude Fable 5.1 or Claude Sonnet 5?
The Claude Fable 5.1 and Claude Sonnet 5 comparison is updated for 2026. Data includes benchmark results, API pricing, context window size and other specifications. For more detailed information, visit the Claude Fable 5.1 or Claude Sonnet 5 page. See also the complete list of AI model comparisons.