Claude Sonnet 5.5 vs DeepSeek V4 Flash
As of Oct 14, 2026, Claude Sonnet 5.5 leads DeepSeek V4 Flash in 5 of 5 shared categories: General LLM, Reasoning, Coding › Web dev, Long context, 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 Flash
Yes. Yes on General LLM (best per dollar); Reasoning (best per dollar). Not the overall leader.
| Category | Claude Sonnet 5.5 | DeepSeek V4 Flash |
|---|---|---|
| General LLM | #27 · #27 in General LLM Margin 18.367346938775512 LMArena leaderboard dataset · Oct 13, 2026 | #75 · #75 in General LLM Margin 51.02040816326531 LMArena leaderboard dataset · Oct 13, 2026 |
| Reasoning | #18 · #18 in Reasoning Margin 13.013698630136986 LMArena leaderboard dataset · Oct 13, 2026 | #72 · #72 in Reasoning Margin 50 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 | — |
| 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 | #30 · #30 in Coding › Web dev Margin 27.10280373831776 LMArena leaderboard dataset · Oct 13, 2026 |
| Long context | #11 · #11 in Long context Margin 7.482993197278915 LMArena leaderboard dataset · Oct 13, 2026 | #69 · #69 in Long context Margin 46.93877551020408 LMArena leaderboard dataset · Oct 13, 2026 |
| Vision | #1 · Co-SOTA · Vision Margin 0 Epoch AI benchmarking hub · Sep 28, 2026 | — |
| Factuality | #16 · #16 in Factuality Margin 12.68656716417911 LMArena leaderboard dataset · Oct 13, 2026 | #66 · #66 in Factuality Margin 50 LMArena leaderboard dataset · Oct 13, 2026 |
Claude Sonnet 5.5: $4.000000000000001 per 1M blended tokens.
DeepSeek V4 Flash: $0.11374999999999999 per 1M blended tokens.
Claude Sonnet 5.5: closed weights.
DeepSeek V4 Flash: open weights.
General LLM: As of Oct 14, 2026, Claude Sonnet 5.5 leads DeepSeek V4 Flash in General LLM at #27 against #75.
Reasoning: As of Oct 14, 2026, Claude Sonnet 5.5 leads DeepSeek V4 Flash in Reasoning at #18 against #72.
Coding › Web dev: As of Oct 14, 2026, Claude Sonnet 5.5 leads DeepSeek V4 Flash in Coding › Web dev at #3 against #30.
Long context: As of Oct 14, 2026, Claude Sonnet 5.5 leads DeepSeek V4 Flash in Long context at #11 against #69.
Factuality: As of Oct 14, 2026, Claude Sonnet 5.5 leads DeepSeek V4 Flash in Factuality at #16 against #66.
Claude Sonnet 5.5 · DeepSeek V4 Flash
Claude Sonnet 5.5 or DeepSeek V4 Flash?
As of Oct 14, 2026, Claude Sonnet 5.5 leads DeepSeek V4 Flash in 5 of 5 shared categories: General LLM, Reasoning, Coding › Web dev, Long context, and Factuality.
Claude Sonnet 5.5 or DeepSeek V4 Flash for General LLM?
As of Oct 14, 2026, Claude Sonnet 5.5 leads DeepSeek V4 Flash in General LLM at #27 against #75.
Claude Sonnet 5.5 or DeepSeek V4 Flash for Reasoning?
As of Oct 14, 2026, Claude Sonnet 5.5 leads DeepSeek V4 Flash in Reasoning at #18 against #72.
Claude Sonnet 5.5 or DeepSeek V4 Flash for Coding › Web dev?
As of Oct 14, 2026, Claude Sonnet 5.5 leads DeepSeek V4 Flash in Coding › Web dev at #3 against #30.