Claude Fable 5.1 vs Claude Sonnet 4.6

Claude Fable 5.1 (Anthropic) versus Claude Sonnet 4.6 (Anthropic): API pricing, context window, capabilities and uptime, from the same data as each model page, at the KumoAPI default channel price. Input costs 10 Credits / M for Claude Fable 5.1 and 3 Credits / M for Claude Sonnet 4.6, so Claude Sonnet 4.6 is 70% cheaper. Context windows are 1M and 1M.

Claude Fable 5.1claude-fable-5-1
Anthropic
Input (prompt)
10Credits / M
Output (completion)
50Credits / M
1M context · 128K output
Claude Fable 5.1 details
Claude Sonnet 4.6claude-sonnet-4-6
Anthropic
Input (prompt)
3Credits / M
Output (completion)
15Credits / M
1M context · 128K output
Claude Sonnet 4.6 details
Lower input price
Claude Sonnet 4.6
70% cheaper
More exclusive capabilities
Claude Fable 5.1
Response Schema, Web Search

Specs side by side

Item
Claude Fable 5.1claude-fable-5-1
Claude Sonnet 4.6claude-sonnet-4-6
Input (prompt) · Credits / M103
Output (completion) · Credits / M5015
Cache read · Credits / M0.250.3
Context window1M1M
Max output128K128K
7-day uptime——
Latest probe latency——
Measured throughput——
ProtocolsAnthropic MessagesAnthropic Messages
Sample monthly cost (10M in + 2M out)20060

Prices are the KumoAPI default channel price in Credits (1 Credit = ¥1); green marks the better side. Uptime and latency come from KumoAPI probes; a dash means the model is not probed yet.

Capabilities

CapabilityClaude Fable 5.1Claude Sonnet 4.6
Vision
Function Calling
Reasoning
Prompt Caching
Streaming
Response Schema
Web Search
Audio
Video
File Input
Realtime
Session
Media
Multipart Form
Binary Response

FAQ

Which is cheaper, Claude Fable 5.1 or Claude Sonnet 4.6?

At the KumoAPI default channel price, Claude Fable 5.1 input costs 10 Credits / M and Claude Sonnet 4.6 input costs 3 Credits / M, so Claude Sonnet 4.6 is 70% cheaper. Output and cache prices are in the specs table above.

Which has the larger context window, Claude Fable 5.1 or Claude Sonnet 4.6?

Claude Fable 5.1 offers 1M tokens, Claude Sonnet 4.6 offers 1M tokens.

Can I switch between Claude Fable 5.1 and Claude Sonnet 4.6 at any time?

Yes. KumoAPI calls every model with the same API key; switching is just changing the model field in the request, and billing is split per model in one console.

How do the capabilities of Claude Fable 5.1 and Claude Sonnet 4.6 differ?

Only Claude Fable 5.1: Response Schema, Web Search. Every other capability is either supported by both or by neither; see the capability table above.

More comparisons

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One API key for both Claude Fable 5.1 and Claude Sonnet 4.6

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