Claude Fable 5 vs Claude Fable 5.1: Specs & Benchmark Comparison

Claude Fable 5 and Claude Fable 5.1 both come from Anthropic, Claude Fable 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 AutomationBench, where Claude Fable 5.1 scores 31.4% against 17.4%; Terminal-Bench 4.0, where Claude Fable 5.1 scores 55.8% against 44.5%. Averaged across everything we track, Claude Fable 5 sits at 59.8% and Claude Fable 5.1 at 59.7%.

On price the two are close: Claude Fable 5 costs $10 per million input tokens and $50 per million output tokens, Claude Fable 5.1 $10 and $50. Both accept a context window of about 1M tokens. Both accept text and images as input.

CharacteristicClaude Fable 5Claude Fable 5.1
CompanyAnthropicAnthropic
Release DateJune 9, 2026September 1, 2026
Parameters——
MultimodalYesYes
Context (input)1.0M1.0M
Context (output)128K128K
Input Price / 1M$10.00$10.00
Output Price / 1M$50.00$50.00
Average Score59.8%59.7%
Benchmarks
AutomationBench17.4%31.4%
Terminal-Bench 4.044.5%55.8%
Humanity's Last Exam64.5%65.0%

Visual Benchmark Comparison

Claude Fable 5
Claude Fable 5.1
AutomationBench0.2 vs 0.3
0.2
0.3
Terminal-Bench 4.00.4 vs 0.6
0.4
0.6
Humanity's Last Exam0.6 vs 0.7
0.6
0.7

Verdict

Claude Fable 5.1 leads in 1 out of 4 comparison categories.

Overall Performance

Both models show comparable average scores: Claude Fable 5 — 0.6, Claude Fable 5.1 — 0.6.

API Cost

API cost is identical: input $10.00/1M, output $50.00/1M tokens.

Context Window

Same context size: 1M tokens.

Recency

Claude Fable 5.1 is newer: released 9/1/2026 vs 6/9/2026.

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Frequently Asked Questions

Which is better for coding — Claude Fable 5 or Claude Fable 5.1?
Direct comparison on the SWE-Bench benchmark is not available. We recommend reviewing other metrics on the comparison page.
Which model is cheaper — Claude Fable 5 or Claude Fable 5.1?
Claude Fable 5 is cheaper for input: $10.00 per 1M tokens vs $10.00.
Which has a larger context window — Claude Fable 5 or Claude Fable 5.1?
Claude Fable 5 supports a larger context: 1,048,576 tokens vs 1,048,576.

The Claude Fable 5 and Claude Fable 5.1 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 or Claude Fable 5.1 page. See also the complete list of AI model comparisons.