# Claude 3.5 Sonnet vs Claude Opus 5.5

As of Oct 15, 2026, Claude 3.5 Sonnet leads Claude Opus 5.5 in 0 of 4 shared categories.

Claude 3.5 Sonnet: price per 1M tokens is unset in the catalog.

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

Claude 3.5 Sonnet: closed weights.

Claude Opus 5.5: closed weights.

- Which to pick, General LLM: As of Oct 15, 2026, Claude Opus 5.5 leads Claude 3.5 Sonnet in General LLM at #2 against #181.
- Which to pick, Reasoning: As of Oct 15, 2026, Claude Opus 5.5 leads Claude 3.5 Sonnet in Reasoning at #1 against #175.
- Which to pick, Science: As of Oct 15, 2026, Claude Opus 5.5 leads Claude 3.5 Sonnet in Science at #31 against #119.
- Which to pick, Long context: As of Oct 15, 2026, Claude Opus 5.5 leads Claude 3.5 Sonnet in Long context at #1 against #163.

As of Oct 15, 2026, Claude 3.5 Sonnet is a former state-of-the-art holder in General LLM (since Aug 28, 2024; sources LMArena Text (style-controlled, overall); methodology v1.0).

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).