Home / Compare / Claude Fable 5.1 vs Claude Opus 5.5

Claude Fable 5.1 vs Claude Opus 5.5

For a typical chat reply (2,000 tokens in, 400 out), Claude Fable 5.1 costs 2.5× as much as Claude Opus 5.5: $40.00 against $16.00 per 1,000 requests at list price on 2026-09-28.

Claude Fable 5.1Claude Opus 5.5
Input, per 1M tokens$10.00$4.00
Output, per 1M tokens$50.00$20.00
Context window1M1M
Classification or routing (600 tokens in, 10 out), per 1,000$6.50$2.60
Chat reply (2,000 in, 400 out), per 1,000$40.00$16.00
Retrieval-augmented answer (8,000 in, 500 out), per 1,000$105$42.00
Confidence signalnono
Tool callingyesyes
BANKING77, correct of 400not measured354

Which one should carry your traffic?

If Claude Opus 5.5 answers your requests as well as Claude Fable 5.1, moving that traffic saves 60% on chat-shaped requests. Averages cannot tell you whether it does for your requests. Claude Opus 5.5 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 Opus 5.5 profile · Measure it on your traffic