Claude Sonnet 5.5 vs DeepSeek V4.1 Flash
As of Oct 14, 2026, Claude Sonnet 5.5 leads DeepSeek V4.1 Flash in 7 of 7 shared categories: General LLM, Reasoning, Science, Coding › Web dev, Long context, Vision, and Factuality.
Claude Sonnet 5.5
Yes. SOTA in co-SOTA in Coding, co-SOTA in Coding › Agentic and co-SOTA in Vision.
DeepSeek V4.1 Flash
Yes. Yes on General LLM (best per dollar); Reasoning (best per dollar). Not the overall leader.
| Category | Claude Sonnet 5.5 | DeepSeek V4.1 Flash |
|---|---|---|
| General LLM | #27 · #27 in General LLM Margin 18.367346938775512 LMArena leaderboard dataset · Oct 13, 2026 | #29 · #29 in General LLM Margin 19.72789115646259 LMArena leaderboard dataset · Oct 13, 2026 |
| Reasoning | #18 · #18 in Reasoning Margin 13.013698630136986 LMArena leaderboard dataset · Oct 13, 2026 | #27 · #27 in Reasoning Margin 19.178082191780817 LMArena leaderboard dataset · Oct 13, 2026 |
| Math | #4 · #4 in Math Margin 6.666666666666671 Epoch AI benchmarking hub · Sep 28, 2026 | #— · Not enough data Margin — LMArena leaderboard dataset · Oct 13, 2026 |
| Science | #3 · #3 in Science Margin — Epoch AI benchmarking hub · Sep 28, 2026 | #36 · #36 in Science Margin — Epoch AI benchmarking hub · Sep 9, 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 | #3 · Near-SOTA · Coding › Web dev Margin 1.8691588785046775 LMArena leaderboard dataset · Oct 13, 2026 | #19 · #19 in Coding › Web dev Margin 16.822429906542055 LMArena leaderboard dataset · Oct 13, 2026 |
| Long context | #11 · #11 in Long context Margin 7.482993197278915 LMArena leaderboard dataset · Oct 13, 2026 | #32 · #32 in Long context Margin 21.768707482993193 LMArena leaderboard dataset · Oct 13, 2026 |
| Vision | #1 · Co-SOTA · Vision Margin 0 Epoch AI benchmarking hub · Sep 28, 2026 | #21 · #21 in Vision Margin 57.89473684210526 Epoch AI benchmarking hub · Sep 9, 2026 |
| Factuality | #16 · #16 in Factuality Margin 12.68656716417911 LMArena leaderboard dataset · Oct 13, 2026 | #22 · #22 in Factuality Margin 17.164179104477626 LMArena leaderboard dataset · Oct 13, 2026 |
| Abstraction (ARC) | — | #8 · #8 in Abstraction (ARC) Margin — Epoch AI benchmarking hub · Sep 9, 2026 |
Claude Sonnet 5.5: $4.000000000000001 per 1M blended tokens.
DeepSeek V4.1 Flash: $0.23463 per 1M blended tokens.
Claude Sonnet 5.5: closed weights.
DeepSeek V4.1 Flash: open weights.
General LLM: As of Oct 14, 2026, Claude Sonnet 5.5 leads DeepSeek V4.1 Flash in General LLM at #27 against #29.
Reasoning: As of Oct 14, 2026, Claude Sonnet 5.5 leads DeepSeek V4.1 Flash in Reasoning at #18 against #27.
Science: As of Oct 14, 2026, Claude Sonnet 5.5 leads DeepSeek V4.1 Flash in Science at #3 against #36.
Coding › Web dev: As of Oct 14, 2026, Claude Sonnet 5.5 leads DeepSeek V4.1 Flash in Coding › Web dev at #3 against #19.
Long context: As of Oct 14, 2026, Claude Sonnet 5.5 leads DeepSeek V4.1 Flash in Long context at #11 against #32.
Vision: As of Oct 14, 2026, Claude Sonnet 5.5 leads DeepSeek V4.1 Flash in Vision at #1 against #21.
Factuality: As of Oct 14, 2026, Claude Sonnet 5.5 leads DeepSeek V4.1 Flash in Factuality at #16 against #22.
Claude Sonnet 5.5 · DeepSeek V4.1 Flash
Claude Sonnet 5.5 or DeepSeek V4.1 Flash?
As of Oct 14, 2026, Claude Sonnet 5.5 leads DeepSeek V4.1 Flash in 7 of 7 shared categories: General LLM, Reasoning, Science, Coding › Web dev, Long context, Vision, and Factuality.
Claude Sonnet 5.5 or DeepSeek V4.1 Flash for General LLM?
As of Oct 14, 2026, Claude Sonnet 5.5 leads DeepSeek V4.1 Flash in General LLM at #27 against #29.
Claude Sonnet 5.5 or DeepSeek V4.1 Flash for Reasoning?
As of Oct 14, 2026, Claude Sonnet 5.5 leads DeepSeek V4.1 Flash in Reasoning at #18 against #27.
Claude Sonnet 5.5 or DeepSeek V4.1 Flash for Science?
As of Oct 14, 2026, Claude Sonnet 5.5 leads DeepSeek V4.1 Flash in Science at #3 against #36.