Home / Compare / Claude Fable 5.1 vs Claude Sonnet 5

Claude Fable 5.1 vs Claude Sonnet 5

For a typical chat reply (2,000 tokens in, 400 out), Claude Fable 5.1 costs 5.0× as much as Claude Sonnet 5: $40.00 against $8.00 per 1,000 requests at list price on 2026-09-28.

Claude Fable 5.1Claude Sonnet 5
Input, per 1M tokens$10.00$2.00
Output, per 1M tokens$50.00$10.00
Context window1M1M
Classification or routing (600 tokens in, 10 out), per 1,000$6.50$1.30
Chat reply (2,000 in, 400 out), per 1,000$40.00$8.00
Retrieval-augmented answer (8,000 in, 500 out), per 1,000$105$21.00
Confidence signalnono
Tool callingyesyes
BANKING77, correct of 400not measured308

Which one should carry your traffic?

If Claude Sonnet 5 answers your requests as well as Claude Fable 5.1, moving that traffic saves 80% on chat-shaped requests. Averages cannot tell you whether it does for your requests. Claude Sonnet 5 does not expose a confidence signal through OpenRouter, so Gimbix would test it as a full replacement rather than a first answer.

Claude Fable 5.1 profile · Claude Sonnet 5 profile · Measure it on your traffic