Home / Compare / Claude Fable 5.1 vs gpt-oss-20b

Claude Fable 5.1 vs gpt-oss-20b

For a typical chat reply (2,000 tokens in, 400 out), Claude Fable 5.1 costs 556× as much as gpt-oss-20b: $40.00 against $0.072 per 1,000 requests at list price on 2026-09-28.

Claude Fable 5.1gpt-oss-20b
Input, per 1M tokens$10.00$0.018
Output, per 1M tokens$50.00$0.09
Context window1M131K
Classification or routing (600 tokens in, 10 out), per 1,000$6.50$0.0117
Chat reply (2,000 in, 400 out), per 1,000$40.00$0.072
Retrieval-augmented answer (8,000 in, 500 out), per 1,000$105$0.189
Confidence signalnoyes
Tool callingyesyes
BANKING77, correct of 400not measured313

Which one should carry your traffic?

If gpt-oss-20b answers your requests as well as Claude Fable 5.1, moving that traffic saves 100% on chat-shaped requests. Averages cannot tell you whether it does for your requests. gpt-oss-20b exposes a confidence signal, so Gimbix can let it answer first and hand unsure cases to Claude Fable 5.1.

Claude Fable 5.1 profile · gpt-oss-20b profile · Measure it on your traffic