# Claude Sonnet 4.6 vs GPT-OSS 20B

> Side-by-side benchmark comparison for Claude Sonnet 4.6 and GPT-OSS 20B across agentic, coding, multimodal, knowledge, reasoning, multilingual, and math tasks.

- Canonical page: https://benchlm.ai/compare/claude-sonnet-4-6-vs-gpt-oss-20b
- Last updated: October 17, 2026

- Shared sourced benchmarks: 4
- HTML indexing: indexable
- Ranking lane: BenchAlign v5.8

## Quick Verdict

Pick Claude Sonnet 4.6 if you want the stronger benchmark profile. GPT-OSS 20B only makes more sense when its price, context window, or workload-specific category wins matter more than the overall score.

## Summary

- Claude Sonnet 4.6 leads overall 55.89 to 33.32.
- The clearest category separation is in agentic, where the averages are 46.3 for Claude Sonnet 4.6 and 14.9 for GPT-OSS 20B.
- The biggest single benchmark swing is HLE in Knowledge, with scores of 49% and 10.9%.
- GPT-OSS 20B is the cheaper option on output tokens, which matters if you expect large responses or heavy interactive use.
- Claude Sonnet 4.6 also has the larger context window at 200K.

## Model Snapshot

| Property | Claude Sonnet 4.6 | GPT-OSS 20B |
|----------|----------|----------|
| Creator | Anthropic | OpenAI |
| Type | Proprietary | Open Weight |
| Reasoning | Non-Reasoning | Non-Reasoning |
| Context | 200K | 128K |
| Overall Score | 55.89 | 33.32 |
| Benchmarks Covered | 28 | 7 |
| Pricing (input/output) | $3.00 / $15.00 | $0.00 / $0.00 |

## Category Breakdown

### Agentic

- Winner: Directional only
- Claude Sonnet 4.6 public-lane score: 46.3 (Supported · #55/128)
- GPT-OSS 20B public-lane score: 14.9 (Estimated · #115/128)

| Benchmark | Claude Sonnet 4.6 | GPT-OSS 20B | Winner |
|-----------|-----------|-----------|--------|
| Terminal-Bench 2.0 | 59.1% | Coming soon | Coming soon |
| OSWorld-Verified | 72.1% | Coming soon | Coming soon |
| Claw-Eval | 67.8% | Coming soon | Coming soon |
| CyberGym | 65.2% | Coming soon | Coming soon |
| Gert Labs | 62.92% | Coming soon | Coming soon |
| OSWorld 2.0 | 8.3% | Coming soon | Coming soon |
| JobBench | 36.9% | Coming soon | Coming soon |
| Terminal-Bench 2.1 (Vals) | 57.3% | Coming soon | Coming soon |
| ApprenticeBench | 2% | Coming soon | Coming soon |
| MazeBench | 0% | Coming soon | Coming soon |

### Coding

- Winner: Directional only
- Claude Sonnet 4.6 public-lane score: 44.7 (Supported · #54/150)
- GPT-OSS 20B public-lane score: 18.2 (Estimated · #123/150)

| Benchmark | Claude Sonnet 4.6 | GPT-OSS 20B | Winner |
|-----------|-----------|-----------|--------|
| SWE-bench Verified | 79.6% | 60.7% | Claude Sonnet 4.6 |
| SWE-Rebench | 60.7% | Coming soon | Coming soon |
| React Native Evals | 80.6% | 71% | Claude Sonnet 4.6 |
| Terminal-Bench 2.0 | 59.1% | Coming soon | Coming soon |
| Vibe Code Bench | 51.48% | Coming soon | Coming soon |
| cursorBench31 | 48.8% | Coming soon | Coming soon |
| FrontierCode 1.1 Main | 24.3% | Coming soon | Coming soon |
| LiveCodeBench (Vals) | 82.1% | Coming soon | Coming soon |
| SWE-bench (Vals) | 77.4% | Coming soon | Coming soon |

### Reasoning

- Winner: Not comparable
- Claude Sonnet 4.6 public-lane score: 62.8 (Unranked · 4 rankable rows)
- GPT-OSS 20B public-lane score: 49.7 (Unranked · 2 rankable rows)

| Benchmark | Claude Sonnet 4.6 | GPT-OSS 20B | Winner |
|-----------|-----------|-----------|--------|
| ARC-AGI-2 | 58.3% | Coming soon | Coming soon |
| ARC-AGI-1 | 86.00% | Coming soon | Coming soon |

### Multimodal & Grounded

- Winner: Not comparable
- Claude Sonnet 4.6 public-lane score: 58.7 (#45/54)
- GPT-OSS 20B public-lane score: Coming soon

| Benchmark | Claude Sonnet 4.6 | GPT-OSS 20B | Winner |
|-----------|-----------|-----------|--------|
| CharXiv | 77.4% | Coming soon | Coming soon |

### Knowledge

- Winner: Claude Sonnet 4.6
- Claude Sonnet 4.6 public-lane score: 55.4 (Supported · #58/184)
- GPT-OSS 20B public-lane score: 33.9 (Supported · #140/184)

| Benchmark | Claude Sonnet 4.6 | GPT-OSS 20B | Winner |
|-----------|-----------|-----------|--------|
| GPQA | 89.9% | 71.5% | Claude Sonnet 4.6 |
| SuperGPQA | 95% | Coming soon | Coming soon |
| MMLU-Pro | 79.2% | Coming soon | Coming soon |
| HLE | 49% | 10.9% | Claude Sonnet 4.6 |
| GPQA Diamond (Vals) | 85.6% | Coming soon | Coming soon |
| MMLU-Pro (Vals) | 87.3% | Coming soon | Coming soon |
| MMLU | Coming soon | 85.3% | Coming soon |

### Instruction Following

- Winner: Directional only
- Claude Sonnet 4.6 public-lane score: 48 (#99/148)
- GPT-OSS 20B public-lane score: 79.2 (#60/148)

### Mathematics

- Winner: Not comparable
- Claude Sonnet 4.6 public-lane score: Coming soon
- GPT-OSS 20B public-lane score: Coming soon

| Benchmark | Claude Sonnet 4.6 | GPT-OSS 20B | Winner |
|-----------|-----------|-----------|--------|
| AIME 2024 | Coming soon | 92.1% | Coming soon |
| AIME 2025 | Coming soon | 91.7% | Coming soon |

## FAQ

### Which is better overall, Claude Sonnet 4.6 or GPT-OSS 20B?

Claude Sonnet 4.6 is ahead overall on BenchLM right now.

### Where is the biggest gap between Claude Sonnet 4.6 and GPT-OSS 20B?

The widest category gap is in agentic, where the averages are 46.3 for Claude Sonnet 4.6 and 14.9 for GPT-OSS 20B.

### How many benchmarks does Claude Sonnet 4.6 cover on BenchLM?

Claude Sonnet 4.6 currently has 28 sourced benchmark scores on BenchLM.

### How many benchmarks does GPT-OSS 20B cover on BenchLM?

GPT-OSS 20B currently has 7 sourced benchmark scores on BenchLM.

## Related Comparisons

- [Claude Sonnet 4.6 vs GPT-OSS 120B](/compare/claude-sonnet-4-6-vs-gpt-oss-120b)
- [GPT-OSS 20B vs GPT-OSS 120B](/compare/gpt-oss-120b-vs-gpt-oss-20b)
- [Claude Sonnet 4.6 vs Claude Opus 5.5](/compare/claude-opus-5-5-vs-claude-sonnet-4-6)
- [GPT-OSS 20B vs Claude Opus 5.5](/compare/claude-opus-5-5-vs-gpt-oss-20b)

## Explore More

- [Claude Sonnet 4.6 profile](/models/claude-sonnet-4-6)
- [GPT-OSS 20B profile](/models/gpt-oss-20b)
- [Compare Pricing](/llm-pricing)
- [Alternative Finder](/tools/alternative-finder)
- [LLM Selector](/tools/llm-selector)
- [Overall Rankings](/best/overall)