# Claude Sonnet 5.5 vs O3

As of Oct 14, 2026, Claude Sonnet 5.5 leads O3 in 6 of 6 shared categories: General LLM, Reasoning, Math, Science, Long context, and Factuality.

Claude Sonnet 5.5: $4.000000000000001 per 1M blended tokens.

O3: $3.5 per 1M blended tokens.

Claude Sonnet 5.5: closed weights.

O3: closed weights.

- Which to pick, General LLM: As of Oct 14, 2026, Claude Sonnet 5.5 leads O3 in General LLM at #27 against #78.
- Which to pick, Reasoning: As of Oct 14, 2026, Claude Sonnet 5.5 leads O3 in Reasoning at #18 against #90.
- Which to pick, Math: As of Oct 14, 2026, Claude Sonnet 5.5 leads O3 in Math at #4 against #20.
- Which to pick, Science: As of Oct 14, 2026, Claude Sonnet 5.5 leads O3 in Science at #3 against #67.
- Which to pick, Long context: As of Oct 14, 2026, Claude Sonnet 5.5 leads O3 in Long context at #11 against #110.
- Which to pick, Factuality: As of Oct 14, 2026, Claude Sonnet 5.5 leads O3 in Factuality at #16 against #105.

As of Oct 14, 2026, Claude Sonnet 5.5 is tied for state of the art in Coding (since Oct 6, 2026; sources Terminal-Bench 4.0; 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).