Claude Opus 5.5 vs Step 3.5 Flash
As of Oct 14, 2026, Claude Opus 5.5 leads Step 3.5 Flash in 4 of 4 shared categories: General LLM, Reasoning, Long context, and Factuality.
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.
Step 3.5 Flash
#99 Best current rank: #99 in Factuality, as of Oct 14, 2026.
| Category | Claude Opus 5.5 | Step 3.5 Flash |
|---|---|---|
| General LLM | #2 · Near-SOTA · General LLM Margin 1.3605442176870781 LMArena leaderboard dataset · Oct 13, 2026 | #123 · #123 in General LLM Margin 83.6734693877551 LMArena leaderboard dataset · Oct 13, 2026 |
| Reasoning | #1 · Co-SOTA · Reasoning Margin 0 LMArena leaderboard dataset · Oct 13, 2026 | #124 · #124 in Reasoning Margin 85.61643835616438 LMArena leaderboard dataset · Oct 13, 2026 |
| Math | #— · Not enough data Margin — LMArena leaderboard dataset · Oct 13, 2026 | #— · Not enough data Margin — LMArena leaderboard dataset · Oct 13, 2026 |
| Science | #31 · #31 in Science Margin — Epoch AI benchmarking hub · Sep 22, 2026 | — |
| Coding | #1 · Co-SOTA · Coding Margin 0 Terminal-Bench Harbor Hub · Oct 6, 2026 | #— · Not enough data Margin — LMArena leaderboard dataset · Oct 13, 2026 |
| 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 | #119 · #119 in Long context Margin 80.95238095238095 LMArena leaderboard dataset · Oct 13, 2026 |
| Vision | #4 · Near-SOTA · Vision Margin 13.15789473684211 Epoch AI benchmarking hub · Sep 22, 2026 | — |
| Factuality | #1 · Co-SOTA · Factuality Margin 0 LMArena leaderboard dataset · Oct 13, 2026 | #99 · #99 in Factuality Margin 74.6268656716418 LMArena leaderboard dataset · Oct 13, 2026 |
| Abstraction (ARC) | #1 · #1 in Abstraction (ARC) Margin — Epoch AI benchmarking hub · Sep 22, 2026 | — |
Claude Opus 5.5: $8.000000000000002 per 1M blended tokens.
Step 3.5 Flash: $0.15 per 1M blended tokens.
Claude Opus 5.5: closed weights.
Step 3.5 Flash: open weights.
General LLM: As of Oct 14, 2026, Claude Opus 5.5 leads Step 3.5 Flash in General LLM at #2 against #123.
Reasoning: As of Oct 14, 2026, Claude Opus 5.5 leads Step 3.5 Flash in Reasoning at #1 against #124.
Long context: As of Oct 14, 2026, Claude Opus 5.5 leads Step 3.5 Flash in Long context at #1 against #119.
Factuality: As of Oct 14, 2026, Claude Opus 5.5 leads Step 3.5 Flash in Factuality at #1 against #99.
Claude Opus 5.5 · Step 3.5 Flash
Claude Opus 5.5 or Step 3.5 Flash?
As of Oct 14, 2026, Claude Opus 5.5 leads Step 3.5 Flash in 4 of 4 shared categories: General LLM, Reasoning, Long context, and Factuality.
Claude Opus 5.5 or Step 3.5 Flash for General LLM?
As of Oct 14, 2026, Claude Opus 5.5 leads Step 3.5 Flash in General LLM at #2 against #123.
Claude Opus 5.5 or Step 3.5 Flash for Reasoning?
As of Oct 14, 2026, Claude Opus 5.5 leads Step 3.5 Flash in Reasoning at #1 against #124.
Claude Opus 5.5 or Step 3.5 Flash for Long context?
As of Oct 14, 2026, Claude Opus 5.5 leads Step 3.5 Flash in Long context at #1 against #119.