Claude Sonnet 5 vs DeepSeek V4.1 Flash
Claude Sonnet 5 
DeepSeek V4.1 Flash Verdict
- Claude Sonnet 5 (high) and DeepSeek V4.1 Flash (max) are level on quality (62.2 vs 61.9).
- Claude Sonnet 5 (high) is stronger in agents & tools, human preference, knowledge, maths, multimodal, reasoning.
- DeepSeek V4.1 Flash (max) is stronger in coding, composite, long context.
- DeepSeek V4.1 Flash (max) is 15× cheaper ($0.262 vs $4.00 per 1M blended).
- DeepSeek V4.1 Flash (max) streams 3.3× faster (215 vs 64 tokens per second).
| Metric | Claude Sonnet 5 (high) | DeepSeek V4.1 Flash (max) |
|---|---|---|
| BenchLeader Index | 62.2 | 61.9 |
| Agents & tools score | 62.0 | 59.6 |
| Coding score | 61.5 | 68.9 |
| Composite score | 69.6 | 74.5 |
| Human preference score | 65.9 | – |
| Knowledge score | 62.4 | 61.7 |
| Long context score | 64.7 | 68.5 |
| Maths score | 66.9 | – |
| Multimodal score | 62.6 | 61.4 |
| Reasoning score | 69.6 | 69.5 |
| Blended price $/M | $4.00 | $0.262 |
| Output speed | 64 tok/s | 215 tok/s |
| Time to first answer | 2.9 s | 10.5 s |
| Context window | 1M | 1M |
| SciCode | 48.6% | – |
| WeirdML | 68.8% | – |
| LMArena Text | 1461 | – |
| LMArena Hard Prompts | 1489 | – |
| LMArena Coding | 1521 | – |
| LMArena WebDev | 1537 | 1614 |
| LMArena Vision | 1277 | – |
| LMArena Agent | 6 | 4.9 |
| LiveBench | – | 81.1% |
| LiveBench Reasoning | – | 86.7% |
| LiveBench Coding | – | 80.0% |
| LiveBench Agentic Coding | – | 77.3% |
| LiveBench Mathematics | – | 93.3% |
| LiveBench Data Analysis | – | 79.3% |
| LiveBench Language | – | 81.2% |
| LiveBench Instruction Following | – | 70.0% |
| AA Intelligence Index | 32.0 | 39.5 |
| AA-LCR | 76.7% | 84.0% |
| MMMU-Pro | – | 77.0% |
| AA-Omniscience | -3.7 | -5.3 |
| Humanity's Last Exam (AA) | 35.7% | 39.3% |
| SciCode (AA) | 54.3% | 51.9% |
| CritPt | 15.1% | 14.3% |
| GDPval (AA) | 40.4% | 56.6% |
| LMArena Maths | 1476 | – |
| LMArena Creative Writing | 1437 | – |
| LMArena Instruction Following | 1465 | – |
| LMArena Multi-turn | 1473 | – |
| LMArena Longer Queries | 1482 | – |
| LMArena Document | 1476 | – |
| DeepSWE | 48.2% | – |
| CursorBench | 56.9% | – |
| ALE-Bench | 1463.1 | – |
Data as of 2026-09-19. Best configuration of each model; every score links to its source on the model pages.
Claude Sonnet 5 vs DeepSeek V4.1 Flash: questions
- Is Claude Sonnet 5 better than DeepSeek V4.1 Flash?
- Claude Sonnet 5 (high) and DeepSeek V4.1 Flash (max) are level on quality (62.2 vs 61.9). The BenchLeader Index combines every independent quality benchmark; Claude Sonnet 5 (high) is ahead overall as of 2026-09-19, but check the category scores for your use.
- Is Claude Sonnet 5 better than DeepSeek V4.1 Flash for coding?
- DeepSeek V4.1 Flash scores higher in coding (69 vs 62 on the category index, where 50 is average).
- Is Claude Sonnet 5 better than DeepSeek V4.1 Flash for agentic tasks?
- Claude Sonnet 5 scores higher in agentic tasks (62 vs 60 on the category index, where 50 is average).
- Which is cheaper, Claude Sonnet 5 or DeepSeek V4.1 Flash?
- DeepSeek V4.1 Flash is cheaper: $0.262 against $4.00 per million tokens, blended at three input tokens per output token.
- Which is faster, Claude Sonnet 5 or DeepSeek V4.1 Flash?
- DeepSeek V4.1 Flash streams faster: 215 against 64 output tokens per second.
- Which has the larger context window?
- Both accept 1M tokens of context.