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Claude Fable 5.1 vs Claude Opus 4.1

At a glance

Anthropic's upgraded Mythos-class flagship, with the biggest gains in agentic coding, long-running agentic workflows, and knowledge work.

1M ctx$10.00/$50.00 per M

High-capability model for complex reasoning and coding.

77200K ctx$15.00/$75.00 per M#38/92
Demos
All demos

No shared demos for these models yet.

AI Output
All AI outputs

No captured outputs for these models yet.

Benchmarks
See rankings
Reasoning
CodingInsufficient data
AgenticInsufficient data
ReasoningInsufficient data
MathInsufficient data
Sources:OpenRouter
Cheaper33%
Capability
Capability—
Reasoning & Knowledge
Graduate Science—
Math
Competition Math—Research Math—
Coding
Real-World Coding—
Agentic
Terminal Tasks—Task Horizon—
Reasoning
Sources:Epoch ECI·Epoch AI·OpenRouter· as of 2026-07-10
Capability
CapabilityECI76.5
Reasoning & Knowledge
Graduate Science73.2%
Math
Competition Math40.0%Research Math5.9%
Coding
Real-World Coding73.3%
Agentic
Terminal Tasks38.0%Task Horizon1.7h
Specs
1M
Context
128K
Max output
Sep 2026
Released
200K
Context
32K
Max output
Aug 2025
Released
Capabilities
Vision
Audio
Reasoning
Vision
Audio
Reasoning
Pricing
Live pricing, shown before you run
Input33%$10.00/M tokens
Output33%$50.00/M tokens
Cache read83%$0.25/M tokens
Cache write33%$12.50/M tokens
Web search$0.01/search
Live pricing, shown before you run
Input$15.00/M tokens
Output$75.00/M tokens
Cache read$1.50/M tokens
Cache write$18.75/M tokens
Web search$0.01/search
Chat with Claude Fable 5.1Go to model
Chat with Claude Opus 4.1Go to model
Frequently Asked Questions: Claude Fable 5.1 vs Claude Opus 4.1▼

Which is better, Claude Fable 5.1 or Claude Opus 4.1?

▼

Both Claude Fable 5.1 and Claude Opus 4.1 are capable AI models. The best choice depends on your specific use case: consider pricing, context window, speed, and which capabilities (vision, reasoning, audio) you need.

Which is cheaper, Claude Fable 5.1 or Claude Opus 4.1?

▼

Claude Fable 5.1 has a lower blended cost. Claude Fable 5.1: $10.00 input / $50.00 output. Claude Opus 4.1: $15.00 input / $75.00 output.

Which has a larger context window, Claude Fable 5.1 or Claude Opus 4.1?

▼

Claude Fable 5.1 has a larger context window: Claude Fable 5.1 supports 1M tokens vs Claude Opus 4.1 at 200K tokens.

Do both Claude Fable 5.1 and Claude Opus 4.1 support vision?

▼

Yes, both Claude Fable 5.1 and Claude Opus 4.1 support vision/image input.

What are the key differences between Claude Fable 5.1 and Claude Opus 4.1?

▼

Claude Fable 5.1 and Claude Opus 4.1 have similar overall capabilities. The main differences lie in pricing, context window size, and provider-specific strengths. Use this comparison page to review all metrics side by side.

Which model should I choose for my use case?

▼

If cost is your priority, choose the cheaper option. If you need the highest intelligence for complex tasks, pick the higher-scoring model. For long documents or codebases, choose the larger context window. You can try both Claude Fable 5.1 and Claude Opus 4.1 for free on idapt.app to see which performs better for your specific needs.

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