Model comparison
Claude Opus 5 vs GPT-OSS 20B
Head-to-head evidence from 13 shared benchmark results across 4 categories. Overall scores shown here use the public BenchAlign v5 ranking lane.
Public leaderboard positions: Claude Opus 5 #1 (Estimated); GPT-OSS 20B #167 (Supported). Intervals and evidence labels describe ranking uncertainty, not a guarantee for a specific workload.
Evidence parity. Claude Opus 5 and GPT-OSS 20B share 13 comparable benchmark results. 0 of 8 categories are comparable. 66 results are unique to Claude Opus 5; 5 to GPT-OSS 20B.
Updated July 24, 2026- Shared results
- 13
- Claude Opus 5 only
- 66
- GPT-OSS 20B only
- 5
- Comparable categories
- 0 / 8
Benchmark data for Claude Opus 5 and GPT-OSS 20B is coming soon on BenchLM.
Confidence note. This is a partial-evidence comparison with 13 shared benchmark results across 4 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 Opus 5 is priced at $5.00 input / $25.00 output per 1M tokens, versus $0.00 input / $0.00 output per 1M tokens 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 Opus 5 | Δ | GPT-OSS 20B |
|---|---|---|---|
| Agentic | Claude Opus 590.8 | MarginNo overlap | GPT-OSS 20BNot measured |
| Coding | Claude Opus 589.5 | MarginNo overlap | GPT-OSS 20BNot measured |
| Reasoning | Claude Opus 590.4 | MarginNo overlap | GPT-OSS 20BNot measured |
| Knowledge | Claude Opus 564.7 | MarginNo overlap | GPT-OSS 20BNot measured |
| Multimodal | Claude Opus 566.9 | 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 Opus 5 | GPT-OSS 20B | Comparison |
|---|---|---|---|
| Input / output priceUSD per 1M tokens | Claude Opus 5$5 input / $25 output | GPT-OSS 20B$0 input / $0 output | GPT-OSS 20B has the lower combined listed price. |
| Generation speedtokens per second | Claude Opus 5Not available | GPT-OSS 20B313 tok/s | A complete speed comparison is not available. |
| First-answer latencyseconds to first token | Claude Opus 5Not available | GPT-OSS 20B0.65 s | A complete latency comparison is not available. |
| Context windowmaximum listed tokens | Claude Opus 5Not available | GPT-OSS 20B128K | A complete context comparison is not available. |
Benchmark Deep Dive
Agentic26 benchmarks
| Benchmark | Claude Opus 5 | GPT-OSS 20B | Result |
|---|---|---|---|
| FrontierBench v0.1Source | 43.3% | — | Not comparable |
| BrowseCompSource | 90.8% | — | Not comparable |
| HLE w/ toolsSource | 64.7% | — | Not comparable |
| DeepSearchQASource | 95.0% | — | Not comparable |
| DRACOSource | 88.6% | — | Not comparable |
| BrowseComp (10-agent, prerelease)Source | 93.6% | — | Not comparable |
| OSWorld 2.0Source | 70.6% | — | Not comparable |
| MCP AtlasSource | 85.8% | — | Not comparable |
| MCP-Atlas claim coverageSource | 89.1% | — | Not comparable |
| LAB all-pass (Anthropic harness)Source | 23.58% | — | Not comparable |
| LAB criterion-pass (Anthropic harness)Source | 93.74% | — | Not comparable |
| LAB all-pass (Harvey held-out)Source | 11.7% | — | Not comparable |
| LAB criterion-pass (Harvey held-out)Source | 94.1% | — | Not comparable |
| GDPval-AASource | 1861 | 567 | Claude Opus 5 leads |
| Toolathlon-VerifiedSource | 80.6% | — | Not comparable |
| Toolathlon Verified Pass@3Source | 87.0% | — | Not comparable |
| Toolathlon Verified Pass³Source | 73.1% | — | Not comparable |
| Toolathlon Verified avg. turnsSource | 23.5 turns | — | Not comparable |
| AutomationBenchSource | 26.0% | — | Not comparable |
| AA Agentic IndexSource | 55.3% | 3.1% | Claude Opus 5 leads |
| GDPval-AASource | 68.0% | 3.4% | Claude Opus 5 leads |
| AA Tau3 BankingSource | 30.3% | — | Not comparable |
| AA BriefcaseSource | 1720 | — | Not comparable |
| aaTerminalBench21Source | 89.1% | — | Not comparable |
| APEX-Agents-AASource | — | 0.7% | Not comparable |
| τ²-bench resultsSource | — | 60.2% | Not comparable |
Coding13 benchmarks
| Benchmark | Claude Opus 5 | GPT-OSS 20B | Result |
|---|---|---|---|
| SWE-bench VerifiedSource | 96% | — | Not comparable |
| SWE-bench ProSource | 79.2% | — | Not comparable |
| SWE MultilingualSource | 89.5% | — | Not comparable |
| SWE MultimodalSource | 59.4% | — | Not comparable |
| deepSweSource | 68.8% | — | Not comparable |
| FrontierCode 1.1 MainSource | 53.4% | — | Not comparable |
| FrontierCode 1.1 ExtendedSource | 63.6% | — | Not comparable |
| ProgramBench (episode 1)Source | 83.0% | — | Not comparable |
| ProgramBenchSource | 93.0% | — | Not comparable |
| cursorBench32Source | 70.0% | — | Not comparable |
| AA Coding IndexSource | 78.0% | 20.7% | Claude Opus 5 leads |
| AA-SciCodeSource | 55.7% | 34.4% | Claude Opus 5 leads |
| React Native EvalsSource | — | 71% | Not comparable |
Reasoning5 benchmarks
Knowledge21 benchmarks
| Benchmark | Claude Opus 5 | GPT-OSS 20B | Result |
|---|---|---|---|
| HLESource | 64.7% | — | Not comparable |
| HLE w/o toolsSource | 56.3% | — | Not comparable |
| HealthBench (raw)Source | 67.1% | — | Not comparable |
| HealthBench (length-adjusted)Source | 57.8% | — | Not comparable |
| HealthBench ProfessionalSource | 59.8% | — | Not comparable |
| HealthBench Professional (raw)Source | 73.4% | — | Not comparable |
| BioMysteryBench (human-solvable)Source | 90.1% | — | Not comparable |
| BioMysteryBench (human-difficult)Source | 49.4% | — | Not comparable |
| SpatialBench VerifiedSource | 72.5% | — | Not comparable |
| SingleCellBenchSource | 60.6% | — | Not comparable |
| ProteinGym HardSource | 47.7% | — | Not comparable |
| Protein DesignSource | 42.5% | — | Not comparable |
| Organic chemistry V2Source | 61.6% | — | Not comparable |
| Protocols (troubleshooting)Source | 61.1% | — | Not comparable |
| Protocols (understanding)Source | 78.4% | — | Not comparable |
| Artificial Analysis Intelligence IndexSource | 60.7% | 14.9% | Claude Opus 5 leads |
| AA-GPQA DiamondSource | 93.2% | 68.8% | Claude Opus 5 leads |
| AA-HLESource | 52.6% | 9.8% | Claude Opus 5 leads |
| AA-Omniscience IndexSource | 31.3% | -63.9% | Claude Opus 5 leads |
| AA-Omniscience AccuracySource | 54.2% | 15.5% | Claude Opus 5 leads |
| AA-Omniscience Hallucination RateSource | 50.1% | 94.1% | Claude Opus 5 leads |
Math5 benchmarks
Multilingual3 benchmarks
Multimodal10 benchmarks
| Benchmark | Claude Opus 5 | GPT-OSS 20B | Result |
|---|---|---|---|
| Chartography (no tools)Source | 29.6% | — | Not comparable |
| Chartography (tools)Source | 83.0% | — | Not comparable |
| BenchCAD Vision2Code (no tools)Source | 0.366 | — | Not comparable |
| BenchCAD Vision2Code (tools)Source | 0.821 | — | Not comparable |
| GDP.pdf (no tools)Source | 83.4% | — | Not comparable |
| GDP.pdf (tools)Source | 85.5% | — | Not comparable |
| OfficeQASource | 78.1% | — | Not comparable |
| OfficeQA ProSource | 66.9% | — | Not comparable |
| AA-MMMU-ProSource | 84.7% | — | Not comparable |
| Design Arena WebsiteSource | — | 882 | Not comparable |
Inst. Following1 benchmarks
| Benchmark | Claude Opus 5 | GPT-OSS 20B | Result |
|---|---|---|---|
| AA-IFBenchSource | — | 65.1% | Not comparable |
Frequently Asked Questions (3)
Can I compare Claude Opus 5 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 Opus 5 and GPT-OSS 20B today?
Claude Opus 5: $5.00 input / $25.00 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.