Compare · ModelsLive · 2 picked · head to head
Claude Opus 4.5 vs gpt-oss-120b
Side by side · benchmarks, pricing, and signals you can act on.
Winner summary
Claude Opus 4.5 wins on 13/15 benchmarks
Claude Opus 4.5 wins 13 of 15 shared benchmarks. Leads in agentic · arena · knowledge.
Category leads
agentic·Claude Opus 4.5arena·Claude Opus 4.5knowledge·Claude Opus 4.5general·Claude Opus 4.5math·gpt-oss-120bsafety·Claude Opus 4.5reasoning·Claude Opus 4.5coding·Claude Opus 4.5
Hype vs Reality
Attention vs performance
Claude Opus 4.5
#179 by perf·#7 by attention
gpt-oss-120b
#127 by perf·no signal
Best value
gpt-oss-120b
171.8x better value than Claude Opus 4.5
Claude Opus 4.5
2.8 pts/$
$15.00/M
gpt-oss-120b
475.4 pts/$
$0.10/M
Vendor risk
Who is behind the model
Anthropic
$965.0B·Tier 1
OpenAI
$840.0B·Tier 1
Head to head
15 benchmarks · 2 models
Claude Opus 4.5gpt-oss-120b
APEX-Agents
Claude Opus 4.5 leads by +14.0
APEX-Agents · evaluates AI agents on complex, multi-step tasks requiring planning, tool use, and autonomous decision-making in realistic environments.
Claude Opus 4.5
18.4
gpt-oss-120b
4.4
Chatbot Arena Elo · Overall
Claude Opus 4.5 leads by +118.2
Claude Opus 4.5
1469.8
gpt-oss-120b
1351.6
Chess Puzzles
gpt-oss-120b leads by +8.4
Chess Puzzles · tests strategic and tactical reasoning by having models solve chess puzzle positions, evaluating lookahead and pattern recognition abilities.
Claude Opus 4.5
7.4
gpt-oss-120b
15.8
Dtbench
Claude Opus 4.5 leads by +22.7
Claude Opus 4.5
83.1
gpt-oss-120b
60.5
GPQA diamond
Claude Opus 4.5 leads by +13.7
Graduate-Level Google-Proof QA (Diamond set) · expert-crafted questions in physics, biology, and chemistry that are difficult even for domain PhDs.
Claude Opus 4.5
81.4
gpt-oss-120b
67.7
Lmca
Claude Opus 4.5 leads by +26.3
Claude Opus 4.5
52.3
gpt-oss-120b
26.1
Metr Time Horizons
Claude Opus 4.5 leads by +18.3
Claude Opus 4.5
75.0
gpt-oss-120b
56.6
Mystery Game Puzzles
Claude Opus 4.5 leads by +14.1
Claude Opus 4.5
14.1
gpt-oss-120b
0.0
OTIS Mock AIME 2024-2025
gpt-oss-120b leads by +2.8
OTIS Mock AIME 2024-2025 · simulated American Invitational Mathematics Examination problems testing advanced problem-solving skills.
Claude Opus 4.5
86.1
gpt-oss-120b
88.9
Fortress
Claude Opus 4.5 leads by +5.3
Claude Opus 4.5
13.6
gpt-oss-120b
8.2
SimpleBench
Claude Opus 4.5 leads by +47.9
SimpleBench · tests fundamental reasoning capabilities with straightforward problems designed to expose gaps in basic logical and spatial thinking.
Claude Opus 4.5
54.4
gpt-oss-120b
6.5
SimpleQA Verified
Claude Opus 4.5 leads by +27.9
SimpleQA Verified · short factual questions with verified answers, measuring factual accuracy and the tendency to hallucinate or provide incorrect information.
Claude Opus 4.5
41.8
gpt-oss-120b
13.9
SWE-Bench Verified (Bash Only)
Claude Opus 4.5 leads by +48.4
SWE-Bench Verified (Bash Only) · a curated subset of SWE-bench where models fix real Python repository bugs using only bash commands, no agent frameworks.
Claude Opus 4.5
74.4
gpt-oss-120b
26.0
Terminal Bench
Claude Opus 4.5 leads by +44.5
Terminal-Bench 2.0 · evaluates AI agents on real terminal-based coding tasks · writing scripts, debugging, running tests, and managing projects entirely through command-line interaction. Tests both code quality and terminal fluency. Claude Opus 4.7 scores 69.4%, demonstrating significant agentic terminal competence.
Claude Opus 4.5
63.1
gpt-oss-120b
18.7
WeirdML
Claude Opus 4.5 leads by +15.6
WeirdML · tests models on unusual and adversarial machine learning tasks that require creative problem-solving beyond standard patterns.
Claude Opus 4.5
63.7
gpt-oss-120b
48.2
Full benchmark table
| Benchmark | Claude Opus 4.5 | gpt-oss-120b |
|---|---|---|
APEX-Agents APEX-Agents · evaluates AI agents on complex, multi-step tasks requiring planning, tool use, and autonomous decision-making in realistic environments. | 18.4 | 4.4 |
Chatbot Arena Elo · Overall | 1469.8 | 1351.6 |
Chess Puzzles Chess Puzzles · tests strategic and tactical reasoning by having models solve chess puzzle positions, evaluating lookahead and pattern recognition abilities. | 7.4 | 15.8 |
Dtbench | 83.1 | 60.5 |
GPQA diamond Graduate-Level Google-Proof QA (Diamond set) · expert-crafted questions in physics, biology, and chemistry that are difficult even for domain PhDs. | 81.4 | 67.7 |
Lmca | 52.3 | 26.1 |
Metr Time Horizons | 75.0 | 56.6 |
Mystery Game Puzzles | 14.1 | 0.0 |
OTIS Mock AIME 2024-2025 OTIS Mock AIME 2024-2025 · simulated American Invitational Mathematics Examination problems testing advanced problem-solving skills. | 86.1 | 88.9 |
Fortress | 13.6 | 8.2 |
SimpleBench SimpleBench · tests fundamental reasoning capabilities with straightforward problems designed to expose gaps in basic logical and spatial thinking. | 54.4 | 6.5 |
SimpleQA Verified SimpleQA Verified · short factual questions with verified answers, measuring factual accuracy and the tendency to hallucinate or provide incorrect information. | 41.8 | 13.9 |
SWE-Bench Verified (Bash Only) SWE-Bench Verified (Bash Only) · a curated subset of SWE-bench where models fix real Python repository bugs using only bash commands, no agent frameworks. | 74.4 | 26.0 |
Terminal Bench Terminal-Bench 2.0 · evaluates AI agents on real terminal-based coding tasks · writing scripts, debugging, running tests, and managing projects entirely through command-line interaction. Tests both code quality and terminal fluency. Claude Opus 4.7 scores 69.4%, demonstrating significant agentic terminal competence. | 63.1 | 18.7 |
WeirdML WeirdML · tests models on unusual and adversarial machine learning tasks that require creative problem-solving beyond standard patterns. | 63.7 | 48.2 |
Pricing · per 1M tokens · projected $/mo at 10M tokens
| Model | Input | Output | Context | Projected $/mo |
|---|---|---|---|---|
| $5.00 | $25.00 | 200K tokens (~100 books) | $100.00 | |
| $0.04 | $0.17 | 131K tokens (~66 books) | $0.70 |
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