# Claude Opus 5.5 vs DeepSeek V4.1 Flash 1017

As of Nov 3, 2026, Claude Opus 5.5 leads DeepSeek V4.1 Flash 1017 in 5 of 5 shared categories: General LLM, Science, Coding, Abstraction (ARC), and Legal.

## Which is better for coding?

As of Nov 3, 2026, Claude Opus 5.5 leads DeepSeek V4.1 Flash 1017 in Coding at #1 against #8.

## Pricing

Claude Opus 5.5: $8 per 1M blended tokens.

DeepSeek V4.1 Flash 1017: $0.52 per 1M blended tokens.

Claude Opus 5.5: closed weights.

DeepSeek V4.1 Flash 1017: open weights.

## Benchmarks side by side

| Benchmark | Claude Opus 5.5 | DeepSeek V4.1 Flash 1017 |
| --- | ---: | ---: |
| ARC-AGI | 98.5% | 94.5% |
| Code Migration | 81.0 | 67.5 |
| Excel Modeling Benchmark (EMB) | 75.8 | 69.2 |
| Finance Agent | 67.8 | 62.9 |
| GPQA Diamond | 90.6% | 93.2% |
| Legal Research Bench | 50.5 | 45.2 |
| SimpleQA Verified | 72.2% | 42.5% |
| Tax Agent Bench | 45.6 | 44.4 |
| Vals Index | 70.2 | 61.3 |
| Vibe Code Bench | 90.3 | 87.7 |

## Verdict

As of Nov 3, 2026, Claude Opus 5.5 leads DeepSeek V4.1 Flash 1017 in 5 of 5 shared categories: General LLM, Science, Coding, Abstraction (ARC), and Legal.

- Which to pick, General LLM: As of Nov 3, 2026, Claude Opus 5.5 leads DeepSeek V4.1 Flash 1017 in General LLM at #1 against #60.
- Which to pick, Science: As of Nov 3, 2026, Claude Opus 5.5 leads DeepSeek V4.1 Flash 1017 in Science at #2 against #17.
- Which to pick, Coding: As of Nov 3, 2026, Claude Opus 5.5 leads DeepSeek V4.1 Flash 1017 in Coding at #1 against #8.
- Which to pick, Abstraction (ARC): As of Nov 3, 2026, Claude Opus 5.5 leads DeepSeek V4.1 Flash 1017 in Abstraction (ARC) at #1 against #8.
- Which to pick, Legal: As of Nov 3, 2026, Claude Opus 5.5 leads DeepSeek V4.1 Flash 1017 in Legal at #5 against #12.

As of Nov 3, 2026, Claude Opus 5.5 is tied for state of the art in General LLM (since Oct 20, 2026; sources LMArena Text (style-controlled, overall) and Vals Index; methodology v1.0).

As of Nov 3, 2026, DeepSeek V4.1 Flash 1017 is state of the art on best per dollar in Coding (since Oct 20, 2026; sources Code Migration; methodology v1.0).

## Related comparisons

- [Claude Opus 5.5 vs Gemini 4 Argon](https://isitsota.com/compare/claude-opus-5-5-vs-gemini-4-argon)
- [Claude Opus 5.5 vs Muse Wonder](https://isitsota.com/compare/claude-opus-5-5-vs-muse-wonder)
- [Claude Opus 5.5 vs GPT-6 Astra](https://isitsota.com/compare/claude-opus-5-5-vs-gpt-6-astra)
- [Claude Opus 5.5 vs Claude Sonnet 5.5](https://isitsota.com/compare/claude-opus-5-5-vs-claude-sonnet-5-5)
- [Claude Opus 5.5 vs Gemini 4 Carbon](https://isitsota.com/compare/claude-opus-5-5-vs-gemini-4-carbon)
- [Claude Fable 5.1 vs Claude Opus 5.5](https://isitsota.com/compare/claude-fable-5-1-vs-claude-opus-5-5)
- [Claude Opus 5.5 vs GPT-6.1 Sol](https://isitsota.com/compare/claude-opus-5-5-vs-gpt-6-1-sol)
- [Claude Fable 5 vs Claude Opus 5.5](https://isitsota.com/compare/claude-fable-5-vs-claude-opus-5-5)