Claude Opus 5.5 vs O3
As of Oct 14, 2026, Claude Opus 5.5 leads O3 in 6 of 6 shared categories: General LLM, Reasoning, Science, Long context, Factuality, and Abstraction (ARC).
Claude Opus 5.5
Yes. SOTA in co-SOTA in Reasoning, co-SOTA in Coding, co-SOTA in Coding › Agentic, Coding › Web dev, co-SOTA in Long context and co-SOTA in Factuality.
O3
It used to be. Was SOTA in General LLM.
| Category | Claude Opus 5.5 | O3 |
|---|---|---|
| General LLM | #2 · Near-SOTA · General LLM Margin 1.3605442176870781 LMArena leaderboard dataset · Oct 13, 2026 | #78 · Was SOTA · General LLM Margin 53.06122448979592 LMArena leaderboard dataset · Oct 13, 2026 |
| Reasoning | #1 · Co-SOTA · Reasoning Margin 0 LMArena leaderboard dataset · Oct 13, 2026 | #90 · Was SOTA · Reasoning Margin 62.32876712328767 LMArena leaderboard dataset · Oct 13, 2026 |
| Math | #— · Not enough data Margin — LMArena leaderboard dataset · Oct 13, 2026 | #20 · Was SOTA · Math Margin 42.22222222222222 Epoch AI benchmarking hub · Apr 16, 2025 |
| Science | #31 · #31 in Science Margin — Epoch AI benchmarking hub · Sep 22, 2026 | #67 · #67 in Science Margin — Epoch AI benchmarking hub · Apr 16, 2025 |
| Coding | #1 · Co-SOTA · Coding Margin 0 Terminal-Bench Harbor Hub · Oct 6, 2026 | #— · Not enough data Margin — Epoch AI benchmarking hub · Apr 16, 2025 |
| Coding › Agentic | #1 · Co-SOTA · Coding › Agentic Margin 0 Terminal-Bench Harbor Hub · Oct 6, 2026 | — |
| Coding › Web dev | #1 · SOTA · Coding › Web dev Margin 0 LMArena leaderboard dataset · Oct 13, 2026 | — |
| Long context | #1 · Co-SOTA · Long context Margin 0 LMArena leaderboard dataset · Oct 13, 2026 | #110 · Was SOTA · Long context Margin 74.82993197278913 LMArena leaderboard dataset · Oct 13, 2026 |
| Vision | #4 · Near-SOTA · Vision Margin 13.15789473684211 Epoch AI benchmarking hub · Sep 22, 2026 | #— · Not enough data Margin — LMArena leaderboard dataset · Oct 9, 2026 |
| Factuality | #1 · Co-SOTA · Factuality Margin 0 LMArena leaderboard dataset · Oct 13, 2026 | #105 · #105 in Factuality Margin 79.1044776119403 LMArena leaderboard dataset · Oct 13, 2026 |
| Abstraction (ARC) | #1 · #1 in Abstraction (ARC) Margin — Epoch AI benchmarking hub · Sep 22, 2026 | #37 · #37 in Abstraction (ARC) Margin — Epoch AI benchmarking hub · Apr 16, 2025 |
Claude Opus 5.5: $8.000000000000002 per 1M blended tokens.
O3: $3.5 per 1M blended tokens.
Claude Opus 5.5: closed weights.
O3: closed weights.
General LLM: As of Oct 14, 2026, Claude Opus 5.5 leads O3 in General LLM at #2 against #78.
Reasoning: As of Oct 14, 2026, Claude Opus 5.5 leads O3 in Reasoning at #1 against #90.
Science: As of Oct 14, 2026, Claude Opus 5.5 leads O3 in Science at #31 against #67.
Long context: As of Oct 14, 2026, Claude Opus 5.5 leads O3 in Long context at #1 against #110.
Factuality: As of Oct 14, 2026, Claude Opus 5.5 leads O3 in Factuality at #1 against #105.
Abstraction (ARC): As of Oct 14, 2026, Claude Opus 5.5 leads O3 in Abstraction (ARC) at #1 against #37.
Claude Opus 5.5 or O3?
As of Oct 14, 2026, Claude Opus 5.5 leads O3 in 6 of 6 shared categories: General LLM, Reasoning, Science, Long context, Factuality, and Abstraction (ARC).
Claude Opus 5.5 or O3 for General LLM?
As of Oct 14, 2026, Claude Opus 5.5 leads O3 in General LLM at #2 against #78.
Claude Opus 5.5 or O3 for Reasoning?
As of Oct 14, 2026, Claude Opus 5.5 leads O3 in Reasoning at #1 against #90.
Claude Opus 5.5 or O3 for Science?
As of Oct 14, 2026, Claude Opus 5.5 leads O3 in Science at #31 against #67.