Home / Compare / Claude Fable 5.1 vs Gemini 3.8 Flash

Claude Fable 5.1 vs Gemini 3.8 Flash

For a typical chat reply (2,000 tokens in, 400 out), Claude Fable 5.1 costs 13× as much as Gemini 3.8 Flash: $40.00 against $3.00 per 1,000 requests at list price on 2026-09-28.

Claude Fable 5.1Gemini 3.8 Flash
Input, per 1M tokens$10.00$0.75
Output, per 1M tokens$50.00$3.75
Context window1M1.05M
Classification or routing (600 tokens in, 10 out), per 1,000$6.50$0.487
Chat reply (2,000 in, 400 out), per 1,000$40.00$3.00
Retrieval-augmented answer (8,000 in, 500 out), per 1,000$105$7.88
Confidence signalnono
Tool callingyesyes
BANKING77, correct of 400not measured331

Which one should carry your traffic?

If Gemini 3.8 Flash answers your requests as well as Claude Fable 5.1, moving that traffic saves 93% on chat-shaped requests. Averages cannot tell you whether it does for your requests. Gemini 3.8 Flash 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 · Gemini 3.8 Flash profile · Measure it on your traffic