# Claude Fable 5.1 vs O3

As of Oct 14, 2026, Claude Fable 5.1 leads O3 in 6 of 6 shared categories: General LLM, Reasoning, Math, Long context, Factuality, and Abstraction (ARC).

Claude Fable 5.1: $20 per 1M blended tokens.

O3: $3.5 per 1M blended tokens.

Claude Fable 5.1: closed weights.

O3: closed weights.

- Which to pick, General LLM: As of Oct 14, 2026, Claude Fable 5.1 leads O3 in General LLM at #6 against #78.
- Which to pick, Reasoning: As of Oct 14, 2026, Claude Fable 5.1 leads O3 in Reasoning at #5 against #90.
- Which to pick, Math: As of Oct 14, 2026, Claude Fable 5.1 leads O3 in Math at #2 against #20.
- Which to pick, Long context: As of Oct 14, 2026, Claude Fable 5.1 leads O3 in Long context at #6 against #110.
- Which to pick, Factuality: As of Oct 14, 2026, Claude Fable 5.1 leads O3 in Factuality at #1 against #105.
- Which to pick, Abstraction (ARC): As of Oct 14, 2026, Claude Fable 5.1 leads O3 in Abstraction (ARC) at #3 against #37.

As of Oct 14, 2026, Claude Fable 5.1 is tied for state of the art in Factuality (since Oct 2, 2026; sources LMArena Text factuality; methodology v1.0).

As of Oct 14, 2026, O3 is a former state-of-the-art holder in General LLM (since Jul 28, 2025; sources LMArena Text (style-controlled, overall); methodology v1.0).