# Claude Sonnet 4.5 vs DeepSeek V4 Flash 0731

> Side-by-side benchmark comparison for Claude Sonnet 4.5 and DeepSeek V4 Flash 0731 across agentic, coding, multimodal, knowledge, reasoning, multilingual, and math tasks.

- Canonical page: https://benchlm.ai/compare/claude-sonnet-4-5-vs-deepseek-v4-flash-0731
- Last updated: September 27, 2026

- Shared sourced benchmarks: 4
- HTML indexing: indexable
- Ranking lane: BenchAlign v5.7

## Quick Verdict

Pick DeepSeek V4 Flash 0731 if you want the stronger benchmark profile. Claude Sonnet 4.5 only makes more sense when its price, context window, or workload-specific category wins matter more than the overall score.

## Summary

- DeepSeek V4 Flash 0731 leads overall 57 to 47.85.
- The clearest category separation is in mathematics, where the averages are 34.6 for Claude Sonnet 4.5 and 79.9 for DeepSeek V4 Flash 0731.
- The biggest single benchmark swing is ARC-AGI-2 in Reasoning, with scores of 13.6% and 61.4%.
- DeepSeek V4 Flash 0731 is the cheaper option on output tokens, which matters if you expect large responses or heavy interactive use.
- DeepSeek V4 Flash 0731 also has the larger context window at 1M.

## Model Snapshot

| Property | Claude Sonnet 4.5 | DeepSeek V4 Flash 0731 |
|----------|----------|----------|
| Creator | Anthropic | DeepSeek |
| Type | Proprietary | Open Weight |
| Reasoning | Non-Reasoning | Reasoning |
| Context | 200K | 1M |
| Overall Score | 47.85 | null |
| Benchmarks Covered | 11 | 42 |
| Pricing (input/output) | $3.00 / $15.00 | $0.14 / $0.28 |

## Category Breakdown

### Agentic

- Winner: Not comparable
- Claude Sonnet 4.5 public-lane score: 34.1 (Estimated · #58/105)
- DeepSeek V4 Flash 0731 public-lane score: Coming soon

| Benchmark | Claude Sonnet 4.5 | DeepSeek V4 Flash 0731 | Winner |
|-----------|-----------|-----------|--------|
| Terminal-Bench 2.0 | 50% | 56.9% | DeepSeek V4 Flash 0731 |
| OSWorld-Verified | 61.4% | Coming soon | Coming soon |
| VITA-Bench | 17.0% | Coming soon | Coming soon |
| Gert Labs | 48.51% | Coming soon | Coming soon |
| JobBench | 27.7% | Coming soon | Coming soon |
| BrowseComp | Coming soon | 73.2% | Coming soon |
| HLE w/ tools | Coming soon | 45.1% | Coming soon |
| MCP Atlas | Coming soon | 69% | Coming soon |
| Toolathlon | Coming soon | 47.8% | Coming soon |
| Terminal-Bench 2.1 | Coming soon | 82.7% | Coming soon |
| CyberGym | Coming soon | 76.7% | Coming soon |
| Toolathlon-Verified | Coming soon | 70.3% | Coming soon |
| Agents' Last Exam | Coming soon | 25.2% | Coming soon |
| AutomationBench | Coming soon | 25.1% | Coming soon |
| Terminal-Bench 2.1 (Vals) | Coming soon | 67.0% | Coming soon |

### Coding

- Winner: Not comparable
- Claude Sonnet 4.5 public-lane score: Coming soon
- DeepSeek V4 Flash 0731 public-lane score: Coming soon

| Benchmark | Claude Sonnet 4.5 | DeepSeek V4 Flash 0731 | Winner |
|-----------|-----------|-----------|--------|
| SWE-bench Verified | 77.2% | 79% | DeepSeek V4 Flash 0731 |
| LiveCodeBench Pass@1-COT | Coming soon | 91.6% | Coming soon |
| Codeforces | Coming soon | 3052.0 | Coming soon |
| SWE-bench Pro | Coming soon | 52.6% | Coming soon |
| SWE Multilingual | Coming soon | 73.3% | Coming soon |
| Terminal-Bench 2.0 | Coming soon | 56.9% | Coming soon |
| Terminal-Bench 2.1 | Coming soon | 82.7% | Coming soon |
| NL2Repo | Coming soon | 54.2% | Coming soon |
| DeepSWE | Coming soon | 54.4% | Coming soon |
| DSBench-FullStack | Coming soon | 68.7% | Coming soon |
| DSBench-Hard | Coming soon | 59.6% | Coming soon |
| VulcanBench v3 | Coming soon | 88.4% | Coming soon |
| OpenHarmony Bench | Coming soon | 53.8% | Coming soon |
| LiveCodeBench (Vals) | Coming soon | 87.3% | Coming soon |
| SWE-bench (Vals) | Coming soon | 88.8% | Coming soon |

### Reasoning

- Winner: Not comparable
- Claude Sonnet 4.5 public-lane score: 19.1 (Unranked · 1 rankable row)
- DeepSeek V4 Flash 0731 public-lane score: 57 (Unranked · 4 rankable rows)

| Benchmark | Claude Sonnet 4.5 | DeepSeek V4 Flash 0731 | Winner |
|-----------|-----------|-----------|--------|
| ARC-AGI-2 | 13.6% | 61.4% | DeepSeek V4 Flash 0731 |
| MRCR 1M | Coming soon | 78.7% | Coming soon |
| CorpusQA 1M | Coming soon | 60.5% | Coming soon |
| ARC-AGI-1 | Coming soon | 89.00% | Coming soon |

### Knowledge

- Winner: Not comparable
- Claude Sonnet 4.5 public-lane score: Coming soon
- DeepSeek V4 Flash 0731 public-lane score: Coming soon

| Benchmark | Claude Sonnet 4.5 | DeepSeek V4 Flash 0731 | Winner |
|-----------|-----------|-----------|--------|
| GPQA | 83.4% | 88.1% | DeepSeek V4 Flash 0731 |
| MMLU-Pro | Coming soon | 86.2% | Coming soon |
| SimpleQA | Coming soon | 34.1% | Coming soon |
| Chinese-SimpleQA | Coming soon | 78.9% | Coming soon |
| GPQA-D | Coming soon | 88.1% | Coming soon |
| HLE | Coming soon | 34.8% | Coming soon |
| GPQA Diamond (Vals) | Coming soon | 89.9% | Coming soon |
| MMLU-Pro (Vals) | Coming soon | 86.2% | Coming soon |

### Mathematics

- Winner: Not comparable
- Claude Sonnet 4.5 public-lane score: 34.6 (Unranked · 2 rankable rows)
- DeepSeek V4 Flash 0731 public-lane score: 79.9 (Unranked · 4 rankable rows)

| Benchmark | Claude Sonnet 4.5 | DeepSeek V4 Flash 0731 | Winner |
|-----------|-----------|-----------|--------|
| AIME 2025 | 87% | Coming soon | Coming soon |
| FrontierMath v2 (Tiers 1-3) | 13.495% | Coming soon | Coming soon |
| FrontierMath v2 (Tier 4) | 4.167% | Coming soon | Coming soon |
| HMMT Feb 2026 | Coming soon | 94.8% | Coming soon |
| IMOAnswerBench | Coming soon | 88.4% | Coming soon |
| Apex | Coming soon | 33.0% | Coming soon |
| Apex Shortlist | Coming soon | 85.7% | Coming soon |

## FAQ

### Which is better overall, Claude Sonnet 4.5 or DeepSeek V4 Flash 0731?

DeepSeek V4 Flash 0731 is ahead overall on BenchLM right now.

### Where is the biggest gap between Claude Sonnet 4.5 and DeepSeek V4 Flash 0731?

The widest category gap is in mathematics, where the averages are 34.6 for Claude Sonnet 4.5 and 79.9 for DeepSeek V4 Flash 0731.

### How many benchmarks does Claude Sonnet 4.5 cover on BenchLM?

Claude Sonnet 4.5 currently has 11 sourced benchmark scores on BenchLM.

### How many benchmarks does DeepSeek V4 Flash 0731 cover on BenchLM?

DeepSeek V4 Flash 0731 currently has 42 sourced benchmark scores on BenchLM.

## Related Comparisons

- [Claude Sonnet 4.5 vs Claude Sonnet 4.5 Thinking](/compare/claude-sonnet-4-5-vs-claude-sonnet-4-5-thinking)
- [DeepSeek V4 Flash 0731 vs Claude Sonnet 4.5 Thinking](/compare/claude-sonnet-4-5-thinking-vs-deepseek-v4-flash-0731)
- [Claude Sonnet 4.5 vs GPT-6 Astra](/compare/claude-sonnet-4-5-vs-gpt-6-astra)
- [DeepSeek V4 Flash 0731 vs GPT-6 Astra](/compare/deepseek-v4-flash-0731-vs-gpt-6-astra)

## Explore More

- [Claude Sonnet 4.5 profile](/models/claude-sonnet-4-5)
- [DeepSeek V4 Flash 0731 profile](/models/deepseek-v4-flash-0731)
- [Compare Pricing](/llm-pricing)
- [Alternative Finder](/tools/alternative-finder)
- [LLM Selector](/tools/llm-selector)
- [Overall Rankings](/best/overall)