Model comparison
Claude Sonnet 4.6 vs GPT-OSS 20B
Head-to-head evidence from 13 shared benchmark results across 6 categories. Overall scores shown here use the public BenchAlign v5 ranking lane.
Public leaderboard positions: Claude Sonnet 4.6 #32 (Supported); GPT-OSS 20B #159 (Supported). Intervals and evidence labels describe ranking uncertainty, not a guarantee for a specific workload.
Evidence parity. Claude Sonnet 4.6 and GPT-OSS 20B share 13 comparable benchmark results. 0 of 8 categories are comparable. 20 results are unique to Claude Sonnet 4.6; 5 to GPT-OSS 20B.
Updated July 20, 2026- Shared results
- 13
- Claude Sonnet 4.6 only
- 20
- GPT-OSS 20B only
- 5
- Comparable categories
- 0 / 8
Benchmark data for Claude Sonnet 4.6 and GPT-OSS 20B is coming soon on BenchLM.
Confidence note. This is a partial-evidence comparison with 13 shared benchmark results across 6 evidence categories; 0 of 8 categories currently have scoreable aggregates for both models. Treat the verdict as directional until coverage is more balanced.
Why this result
BenchLM has partial data for these models, but not enough overlapping benchmark coverage to produce a fair score-level comparison yet.
Claude Sonnet 4.6 is priced at $3.00 input / $15.00 output per 1M tokens, versus $0.00 input / $0.00 output per 1M tokens for GPT-OSS 20B. Claude Sonnet 4.6 has the larger context window at 200K, compared with 128K for GPT-OSS 20B.
Category breakdown
Exact category averages are shown below. Not measured means BenchLM does not have enough sourced public coverage for that model and category.
| Category | Claude Sonnet 4.6 | Δ | GPT-OSS 20B |
|---|---|---|---|
| Agentic | Claude Sonnet 4.665.2 | MarginNo overlap | GPT-OSS 20BNot measured |
| Coding | Claude Sonnet 4.669.1 | MarginNo overlap | GPT-OSS 20BNot measured |
| Knowledge | Claude Sonnet 4.666.0 | MarginNo overlap | GPT-OSS 20BNot measured |
| Math | Claude Sonnet 4.626.4 | MarginNo overlap | GPT-OSS 20BNot measured |
| Multimodal | Claude Sonnet 4.677.4 | MarginNo overlap | GPT-OSS 20BNot measured |
Operational comparison
Runtime and commercial metrics are compared only when both models have a complete sourced value.
| Metric | Claude Sonnet 4.6 | GPT-OSS 20B | Comparison |
|---|---|---|---|
| Input / output priceUSD per 1M tokens | Claude Sonnet 4.6$3 input / $15 output | GPT-OSS 20B$0 input / $0 output | GPT-OSS 20B has the lower combined listed price. |
| Generation speedtokens per second | Claude Sonnet 4.644 tok/s | GPT-OSS 20B313 tok/s | GPT-OSS 20B has the higher measured throughput. |
| First-answer latencyseconds to first token | Claude Sonnet 4.61.48 s | GPT-OSS 20B0.65 s | GPT-OSS 20B reaches the first token sooner. |
| Context windowmaximum listed tokens | Claude Sonnet 4.6200K | GPT-OSS 20B128K | Claude Sonnet 4.6 lists the larger context window. |
Benchmark Deep Dive
Agentic12 benchmarks
| Benchmark | Claude Sonnet 4.6 | GPT-OSS 20B | Result |
|---|---|---|---|
| Terminal-Bench 2.0Source | 59.1% | — | Not comparable |
| OSWorld-VerifiedSource | 72.1% | — | Not comparable |
| Claw-EvalSource | 67.8% | — | Not comparable |
| CyberGymSource | 65.2% | — | Not comparable |
| τ²-bench resultsSource | 79.5% | 60.2% | Claude Sonnet 4.6 leads |
| Gert LabsSource | 62.92% | — | Not comparable |
| OSWorld 2.0Source | 8.3% | — | Not comparable |
| JobBenchSource | 36.9% | — | Not comparable |
| AA Agentic IndexSource | — | 3.1% | Not comparable |
| APEX-Agents-AASource | — | 0.7% | Not comparable |
| GDPval-AASource | — | 3.0% | Not comparable |
| GDPval-AASource | — | 559 | Not comparable |
Coding8 benchmarks
| Benchmark | Claude Sonnet 4.6 | GPT-OSS 20B | Result |
|---|---|---|---|
| SWE-bench VerifiedSource | 79.6% | — | Not comparable |
| SWE-RebenchSource | 60.7% | — | Not comparable |
| React Native EvalsSource | 80.6% | 71% | Claude Sonnet 4.6 leads |
| Vibe Code BenchSource | 51.48% | — | Not comparable |
| cursorBench31Source | 48.8% | — | Not comparable |
| AA-SciCodeSource | 46.9% | 34.4% | Claude Sonnet 4.6 leads |
| FrontierCode 1.1 MainSource | 24.3% | — | Not comparable |
| AA Coding IndexSource | — | 20.7% | Not comparable |
Reasoning2 benchmarks
Knowledge10 benchmarks
| Benchmark | Claude Sonnet 4.6 | GPT-OSS 20B | Result |
|---|---|---|---|
| GPQASource | 89.9% | — | Not comparable |
| SuperGPQASource | 95% | — | Not comparable |
| MMLU-ProSource | 79.2% | — | Not comparable |
| HLESource | 49% | — | Not comparable |
| Artificial Analysis Intelligence IndexSource | 35.9% | 14.9% | Claude Sonnet 4.6 leads |
| AA-GPQA DiamondSource | 79.9% | 68.8% | Claude Sonnet 4.6 leads |
| AA-HLESource | 13.2% | 9.8% | Claude Sonnet 4.6 leads |
| AA-Omniscience IndexSource | -2.9% | -63.9% | Claude Sonnet 4.6 leads |
| AA-Omniscience AccuracySource | 38.0% | 15.5% | Claude Sonnet 4.6 leads |
| AA-Omniscience Hallucination RateSource | 65.9% | 94.1% | Claude Sonnet 4.6 leads |
Math2 benchmarks
Multimodal3 benchmarks
Inst. Following1 benchmarks
| Benchmark | Claude Sonnet 4.6 | GPT-OSS 20B | Result |
|---|---|---|---|
| AA-IFBenchSource | 41.2% | 65.1% | GPT-OSS 20B leads |
Frequently Asked Questions (3)
Can I compare Claude Sonnet 4.6 and GPT-OSS 20B on BenchLM yet?
Not fully yet. BenchLM is tracking both models, but the sourced benchmark breakdown for this comparison is still coming soon.
Why does this comparison show “coming soon”?
BenchLM only shows category winners and benchmark-level calls when we have sourced results that can be compared fairly. For these models, the public benchmark coverage is not complete enough yet.
What data is available for Claude Sonnet 4.6 and GPT-OSS 20B today?
Claude Sonnet 4.6: $3.00 input / $15.00 output per 1M tokens GPT-OSS 20B: $0.00 input / $0.00 output per 1M tokens Both model pages still include creator, context window, reasoning mode, and other metadata while benchmark coverage fills in.
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