Gemini 3 Pro vs Claude Opus 4.5: Comprehensive AI Model Comparison

Both Google's Gemini 3 Pro (released November 18, 2025) and Anthropic's Claude Opus 4.5 (released November 24, 2025) represent frontier AI models. This comparison analyzes their capabilities, performance, pricing, and suitable use cases.

Release Timeline

Gemini 3 Pro: November 18, 2025
Claude Opus 4.5: November 24, 2025

Benchmark Performance

Coding Benchmarks

| Benchmark | Gemini 3 Pro | Claude Opus 4.5 | Winner | | -------------------------- | ------------ | -------------------------- | ------ | | SWE-bench Verified | 62.2% | 80.9% | Claude | | Terminal-Bench | - | 15% better than Sonnet 4.5 | Claude | | SWE-bench Multilingual | - | Leads 7/8 languages | Claude |

Claude Opus 4.5 demonstrates superior coding capabilities, achieving 80.9% on SWE-bench Verified compared to Gemini 3 Pro's 62.2%. Anthropic reports that Opus 4.5 "outscored every human candidate" on their internal engineering tests within a 2-hour time limit.

Reasoning and Mathematics

| Benchmark | Gemini 3 Pro | Claude Opus 4.5 | | ------------- | ------------ | -------------------- | | GPQA | 91.9% | - | | AIME | - | Frontier performance | | HLE | 37.5% | - | | MathArena | 23.4% | - |

Gemini 3 Pro shows strong mathematics performance with 91.9% on GPQA and 23.4% on MathArena. Direct AIME comparison data unavailable, though both models claim strong mathematical reasoning.

Agentic Capabilities

| Benchmark | Gemini 3 Pro | Claude Opus 4.5 | | ------------------- | ------------ | ------------------------------------------------------ | | OSWorld | 24.4% | 66.3% | | BrowseComp-Plus | - | 85.3% (with context management) | | τ2-bench | - | Creative problem-solving beyond benchmark expectations |

Claude Opus 4.5 leads significantly in computer use and agentic tasks, scoring 66.3% on OSWorld versus Gemini 3 Pro's 24.4%. Anthropic reports that Opus 4.5 excels at "long-horizon, autonomous tasks" with sustained reasoning over 30+ hour coding sessions.

General Knowledge

| Benchmark | Gemini 3 Pro | Claude Opus 4.5 | | ----------- | ------------ | ------------------------------- | | MMLU | 88.0% | State-of-the-art across domains | | LMArena | 1501 Elo | - |

Context Windows

Gemini 3 Pro: 1,000,000 tokens input, 64,000 tokens output
Claude Opus 4.5: 200,000 tokens context window

Gemini 3 Pro offers 5x larger input context (1M vs 200K tokens), enabling processing of longer documents and codebases in a single request.

Pricing

Standard Pricing

| Model | Input Cost | Output Cost | Context Threshold | | ------------------- | ---------- | ----------- | ----------------- | | Gemini 3 Pro | $2/MTok | $12/MTok | Under 200K tokens | | Gemini 3 Pro | $4/MTok | $18/MTok | 200K+ tokens | | Claude Opus 4.5 | $5/MTok | $25/MTok | All requests |

Gemini 3 Pro costs less for standard use cases (under 200K context): $2/$12 versus Claude's $5/$25 per million tokens.

Cost Optimization Features

Gemini 3 Pro:

Cached content: $0.50/$2.50 per million tokens (under 200K) or $1/$4 (200K+)

Claude Opus 4.5:

Prompt caching: Up to 90% savings
Batch processing: 50% savings
Effort parameter: 76% fewer output tokens at medium effort (matching Sonnet 4.5 performance)

Claude's effort parameter provides dynamic cost control. At medium effort, Opus 4.5 matches Sonnet 4.5's SWE-bench Verified score while using 76% fewer tokens. At maximum effort, it exceeds Sonnet performance by 4.3 points while using 48% fewer tokens.

Special Features

Gemini 3 Pro

API Parameters:

thinking_level: Control reasoning depth ("BASIC", "ADVANCED", "DEEP")
media_resolution: Image quality control ("AUTO", "LOW", "MEDIUM", "HIGH")
thought_signatures: Debug internal reasoning process

Model Variants:

Gemini 3 Deep Think: Enhanced reasoning variant (41.0% HLE, 93.8% GPQA, 45.1% ARC-AGI-2)

Claude Opus 4.5

API Features:

effort parameter: Balance performance vs latency/cost
Context management: Automatic summarization for long conversations
Memory capabilities: Maintain context across conversations
Advanced tool use: Multi-agent coordination support
Hybrid reasoning: Instant responses or extended thinking mode

Platform Tools:

Claude Agent SDK
Context compaction
Client-side compaction SDK

Safety and Alignment

Gemini 3 Pro

Google conducted extensive red-teaming across content safety, bias, adversarial attacks, and misuse scenarios. Results not publicly quantified in accessed materials.

Claude Opus 4.5

Anthropic provides quantified safety metrics:

"Most robustly aligned model we have released to date"
Industry-leading resistance to prompt injection attacks (tested by Gray Swan)
Reduced concerning behavior scores across misalignment categories
Lower sycophancy and deception tendencies

Use Cases

Gemini 3 Pro Strengths

Long-context applications: 1M token input enables entire codebase analysis
Cost-sensitive workflows: Lower base pricing ($2/$12 vs $5/$25)
Mathematical reasoning: 91.9% GPQA, strong MathArena performance
Multimodal tasks: Configurable media resolution
Debug reasoning: thought_signatures for transparency

Claude Opus 4.5 Strengths

Software engineering: 80.9% SWE-bench Verified, multi-day projects in hours
AI agents: 66.3% OSWorld, 30+ hour autonomous coding capability
Computer use: State-of-the-art screen interaction and control
Enterprise workflows: Spreadsheets, slides, document creation
Token efficiency: 50-75% fewer tool calling/build errors
Prompt injection resistance: Industry-leading safety against attacks

Migration Considerations

From Gemini 3 Pro to Claude Opus 4.5

Advantages:

30% improvement in SWE-bench Verified (62.2% → 80.9%)
172% improvement in OSWorld (24.4% → 66.3%)
Better agentic capabilities and multi-step reasoning
Stronger safety guarantees against prompt injection
Token efficiency with effort parameter

Trade-offs:

80% smaller context window (1M → 200K tokens)
2.5x higher base cost ($2/$12 → $5/$25)
May require code changes for context window limitations

From Claude Opus 4.5 to Gemini 3 Pro

Advantages:

5x larger context window (200K → 1M tokens)
60% lower base cost ($5/$25 → $2/$12 for under 200K contexts)
Explicit reasoning control (thinking_level parameter)
Strong mathematics performance (91.9% GPQA)

Trade-offs:

Lower coding benchmark scores (SWE-bench: 80.9% → 62.2%)
Reduced agentic capabilities (OSWorld: 66.3% → 24.4%)
Less mature safety documentation for prompt injection

Integration and Availability

Gemini 3 Pro

Access:

Google AI Studio
Vertex AI
Available in 38 countries
Free tier with rate limits

Model Names:

gemini-pro-3.0
gemini-deep-think-3.0

Claude Opus 4.5

Access:

Claude API
Amazon Bedrock
Google Cloud Vertex AI
Microsoft Foundry
Claude apps (Pro, Max, Team, Enterprise)

Model Name:

claude-opus-4-5-20251101

Performance-to-Cost Analysis

For a 100K token input, 10K token output request:

Gemini 3 Pro:

Cost: $0.32 (($2 × 0.1) + ($12 × 0.01))
SWE-bench Verified: 62.2%
OSWorld: 24.4%

Claude Opus 4.5:

Cost: $0.75 (($5 × 0.1) + ($25 × 0.01))
SWE-bench Verified: 80.9%
OSWorld: 66.3%

Claude Opus 4.5 (medium effort):

Cost: ~$0.29 (($5 × 0.1) + ($25 × 0.01 × 0.24))
SWE-bench Verified: ~77.2% (matches Sonnet 4.5)
Token efficiency: 76% reduction

At medium effort, Claude Opus 4.5 achieves comparable cost to Gemini 3 Pro while maintaining superior coding performance.

Recommendations

Choose Gemini 3 Pro for:

Applications requiring over 200K token context windows
Budget-constrained projects with high API call volume
Mathematical reasoning and academic research
Multimodal applications with configurable media quality
Workflows benefiting from explicit reasoning control

Choose Claude Opus 4.5 for:

Production software engineering and code generation
Autonomous AI agents and computer use applications
Enterprise workflows involving spreadsheets, slides, documents
Security-critical applications requiring prompt injection resistance
Long-running, multi-step tasks requiring sustained reasoning
Projects where token efficiency matters (with effort parameter)

Conclusion

Gemini 3 Pro and Claude Opus 4.5 target different optimization points. Gemini 3 Pro prioritizes context length (1M tokens) and cost efficiency ($2/$12 base pricing), making it suitable for long-document analysis and cost-sensitive applications. Claude Opus 4.5 prioritizes coding quality (80.9% SWE-bench), agentic capabilities (66.3% OSWorld), and safety, making it the stronger choice for software engineering, autonomous agents, and enterprise workflows.

The 30% performance gap in SWE-bench Verified (62.2% vs 80.9%) and 172% gap in OSWorld (24.4% vs 66.3%) demonstrate Claude Opus 4.5's leadership in real-world coding and computer use tasks. However, Gemini 3 Pro's 5x larger context window and lower base cost create compelling advantages for specific use cases.

For cost-conscious software engineering, Claude Opus 4.5's effort parameter offers a middle ground: at medium effort, it achieves ~77% SWE-bench Verified performance at comparable cost to Gemini 3 Pro's $0.32 per 100K/10K request.

Both models represent significant advances in AI capabilities, released within six days of each other in November 2025.