Model comparison
Claude Sonnet 4.5 vs GPT-OSS 120B
Head-to-head evidence from 2 shared benchmark results across 2 categories. Overall scores shown here use the public BenchAlign v5 ranking lane.
Public leaderboard positions: Claude Sonnet 4.5 #96 (Estimated); GPT-OSS 120B #116 (Supported). Intervals and evidence labels describe ranking uncertainty, not a guarantee for a specific workload.
Evidence parity. Claude Sonnet 4.5 and GPT-OSS 120B share 2 comparable benchmark results. 0 of 8 categories are comparable. 10 results are unique to Claude Sonnet 4.5; 24 to GPT-OSS 120B.
Updated July 22, 2026- Shared results
- 2
- Claude Sonnet 4.5 only
- 10
- GPT-OSS 120B only
- 24
- Comparable categories
- 0 / 8
Benchmark data for Claude Sonnet 4.5 and GPT-OSS 120B is coming soon on BenchLM.
Confidence note. This is a partial-evidence comparison with 2 shared benchmark results across 2 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 4.5 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 120B. Claude Sonnet 4.5 has the larger context window at 200K, compared with 128K for GPT-OSS 120B.
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 4.5 | Δ | GPT-OSS 120B |
|---|---|---|---|
| Agentic | Claude Sonnet 4.555.4 | MarginNo overlap | GPT-OSS 120BNot measured |
| Coding | Claude Sonnet 4.577.2 | MarginNo overlap | GPT-OSS 120BNot measured |
| Reasoning | Claude Sonnet 4.513.6 | MarginNo overlap | GPT-OSS 120BNot measured |
| Knowledge | Claude Sonnet 4.583.4 | MarginNo overlap | GPT-OSS 120BNot measured |
| Math | Claude Sonnet 4.511.2 | MarginNo overlap | GPT-OSS 120BNot measured |
Operational comparison
Runtime and commercial metrics are compared only when both models have a complete sourced value.
| Metric | Claude Sonnet 4.5 | GPT-OSS 120B | Comparison |
|---|---|---|---|
| Input / output priceUSD per 1M tokens | Claude Sonnet 4.5$3 input / $15 output | GPT-OSS 120B$0 input / $0 output | GPT-OSS 120B has the lower combined listed price. |
| Generation speedtokens per second | Claude Sonnet 4.5Not available | GPT-OSS 120B262 tok/s | A complete speed comparison is not available. |
| First-answer latencyseconds to first token | Claude Sonnet 4.5Not available | GPT-OSS 120B0.79 s | A complete latency comparison is not available. |
| Context windowmaximum listed tokens | Claude Sonnet 4.5200K | GPT-OSS 120B128K | Claude Sonnet 4.5 lists the larger context window. |
Benchmark Deep Dive
Agentic12 benchmarks
| Benchmark | Claude Sonnet 4.5 | GPT-OSS 120B | Result |
|---|---|---|---|
| Terminal-Bench 2.0Source | 50% | — | Not comparable |
| OSWorld-VerifiedSource | 61.4% | — | Not comparable |
| VITA-BenchSource | 17.0% | — | Not comparable |
| Gert LabsSource | 48.51% | 29.61% | Claude Sonnet 4.5 leads |
| JobBenchSource | 27.7% | — | Not comparable |
| AA Agentic IndexSource | — | 13.2% | Not comparable |
| APEX-Agents-AASource | — | 3.1% | Not comparable |
| τ²-bench resultsSource | — | 65.8% | Not comparable |
| GDPval-AASource | — | 15.0% | Not comparable |
| GDPval-AASource | — | 799 | Not comparable |
| AA EnterpriseOps-GymSource | — | 25.5% | Not comparable |
| AA ITBenchSource | — | 5.6% | Not comparable |
Coding5 benchmarks
Reasoning3 benchmarks
Knowledge9 benchmarks
| Benchmark | Claude Sonnet 4.5 | GPT-OSS 120B | Result |
|---|---|---|---|
| GPQASource | 83.4% | — | Not comparable |
| Artificial Analysis Intelligence IndexSource | — | 23.8% | Not comparable |
| AA-GPQA DiamondSource | — | 78.2% | Not comparable |
| AA-HLESource | — | 18.5% | Not comparable |
| AA-Omniscience IndexSource | — | -50.0% | Not comparable |
| AA-Omniscience AccuracySource | — | 21.5% | Not comparable |
| AA-Omniscience Hallucination RateSource | — | 91.2% | Not comparable |
| AA Openness IndexSource | — | 38.9% | Not comparable |
| AA MMLU-ProSource | — | 80.8% | Not comparable |
Math4 benchmarks
Multilingual1 benchmarks
| Benchmark | Claude Sonnet 4.5 | GPT-OSS 120B | Result |
|---|---|---|---|
| AA Global-MMLU-LiteSource | — | 82.8% | Not comparable |
Multimodal1 benchmarks
| Benchmark | Claude Sonnet 4.5 | GPT-OSS 120B | Result |
|---|---|---|---|
| Design Arena WebsiteSource | 1219 | 998 | Claude Sonnet 4.5 leads |
Inst. Following1 benchmarks
| Benchmark | Claude Sonnet 4.5 | GPT-OSS 120B | Result |
|---|---|---|---|
| AA-IFBenchSource | — | 69.0% | Not comparable |
Frequently Asked Questions (3)
Can I compare Claude Sonnet 4.5 and GPT-OSS 120B 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 4.5 and GPT-OSS 120B today?
Claude Sonnet 4.5: $3.00 input / $15.00 output per 1M tokens GPT-OSS 120B: $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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