# 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: $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.

- Which to pick, General LLM: As of Oct 14, 2026, Claude Sonnet 5.5 leads DeepSeek V4.1 Flash in General LLM at #27 against #29.
- Which to pick, Reasoning: As of Oct 14, 2026, Claude Sonnet 5.5 leads DeepSeek V4.1 Flash in Reasoning at #18 against #27.
- Which to pick, Science: As of Oct 14, 2026, Claude Sonnet 5.5 leads DeepSeek V4.1 Flash in Science at #3 against #36.
- Which to pick, 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.
- Which to pick, Long context: As of Oct 14, 2026, Claude Sonnet 5.5 leads DeepSeek V4.1 Flash in Long context at #11 against #32.
- Which to pick, Vision: As of Oct 14, 2026, Claude Sonnet 5.5 leads DeepSeek V4.1 Flash in Vision at #1 against #21.
- Which to pick, Factuality: As of Oct 14, 2026, Claude Sonnet 5.5 leads DeepSeek V4.1 Flash in Factuality at #16 against #22.

As of Oct 14, 2026, Claude Sonnet 5.5 is tied for state of the art in Coding (since Oct 6, 2026; sources Terminal-Bench 4.0; methodology v1.0).

As of Oct 14, 2026, DeepSeek V4.1 Flash is state of the art on best per dollar in General LLM (since Oct 14, 2026; sources LMArena Text (style-controlled, overall); methodology v1.0).