# Claude Opus 5.5 vs O1

As of Oct 15, 2026, Claude Opus 5.5 leads O1 in 5 of 5 shared categories: General LLM, Reasoning, Science, Long context, and Abstraction (ARC).

Claude Opus 5.5: $8.000000000000002 per 1M blended tokens.

O1: $26.25 per 1M blended tokens.

Claude Opus 5.5: closed weights.

O1: closed weights.

- Which to pick, General LLM: As of Oct 15, 2026, Claude Opus 5.5 leads O1 in General LLM at #2 against #112.
- Which to pick, Reasoning: As of Oct 15, 2026, Claude Opus 5.5 leads O1 in Reasoning at #1 against #117.
- Which to pick, Science: As of Oct 15, 2026, Claude Opus 5.5 leads O1 in Science at #31 against #77.
- Which to pick, Long context: As of Oct 15, 2026, Claude Opus 5.5 leads O1 in Long context at #1 against #108.
- Which to pick, Abstraction (ARC): As of Oct 15, 2026, Claude Opus 5.5 leads O1 in Abstraction (ARC) at #1 against #57.

As of Oct 15, 2026, Claude Opus 5.5 is tied for state of the art in Reasoning (since Oct 2, 2026; sources LMArena Text (style-controlled, hard prompts); methodology v1.0).

As of Oct 15, 2026, O1 is a former state-of-the-art holder in General LLM (since Jan 28, 2025; sources LMArena Text (style-controlled, overall); methodology v1.0).