The race for AI supremacy reached new heights in late 2025 with three groundbreaking releases: OpenAI's GPT-5.2, Anthropic's Claude Opus 4.5, and Google's Gemini 3 Pro. Each model brings unique strengths—GPT-5.2 dominates in reasoning and speed, Claude Opus 4.5 leads in coding tasks, while Gemini 3 Pro excels with its massive context window and multimodal capabilities. This comprehensive comparison breaks down performance benchmarks, pricing, and real-world applications to help you choose the right model for your needs.
Quick Comparison Table
| Feature | GPT-5.2 | Claude Opus 4.5 | Gemini 3 Pro |
|---|---|---|---|
| Release Date | December 2025 | November 2025 | November 2025 |
| Context Window | 400K tokens | Standard | 1M tokens |
| Coding (SWE-bench) | 74.9% | 80.9% | 76.8% |
| Reasoning (MMLU) | 94.2% | 93.8% | ~92% |
| Speed | 187 tokens/sec | ~50 tokens/sec | 650ms avg (Flash) |
| Hallucination Rate | 4.8% | 58% (low) | Moderate |
| Pricing (Input/Output) | $20/$60 per 1M | $5/$25 per 1M | Varies by variant |
| Best For | Real-time reasoning | Complex coding | Multimodal analysis |
GPT-5.2: The Reasoning Powerhouse
OpenAI released GPT-5 in August 2025, followed by GPT-5.1 in November and GPT-5.2 in December, marking their most ambitious model series yet.
What's New in 2026
Breakthrough Performance:
- 100% accuracy on AIME 2025 mathematics competition
- 93.2% on GPQA Diamond (graduate-level science questions)
- 40.3% on FrontierMath (expert-level mathematics)
- 52.9% on ARC-AGI-2 (3.1x improvement over GPT-5.1)
Technical Capabilities:
- 400K token context window with 128K max output tokens
- 65% fewer hallucinations compared to GPT-4 models (down to 4.8%)
- Unified architecture combining fast responses with deep reasoning
- 187 tokens per second processing speed—3.8x faster than Claude
Developer Features:
- Reasoning token support for enhanced problem-solving
- Free-form tool calls returning SQL, Python, or custom code instead of rigid JSON
- Model Context Protocol (MCP) support
- Native integrations with Gmail, Google Calendar, Drive, and SharePoint
GPT-5.2 Performance Benchmarks
The improvements over GPT-4o are substantial:
| Benchmark | GPT-4o | GPT-5.2 | Improvement |
|---|---|---|---|
| SWE-bench Verified | 54.6% | 74.9% | +20.3 p.p. |
| GPQA (Science) | 70.1% | 85.7% | +15.6 p.p. |
| AIME 2025 (Math) | ~45% | 100% | +55 p.p. |
| Hallucination Rate | 11-15% | 4.8% | -67% |
Pricing
GPT-5.2 costs $20 per million input tokens and $60 per million output tokens. While more expensive than Claude, the speed advantage often results in lower total costs for high-volume applications.
Claude Opus 4.5: The Coding Champion
Released November 24, 2025, Claude Opus 4.5 represents Anthropic's most powerful model and ranks as the #2 most intelligent model globally in the Artificial Analysis Intelligence Index.
Why Developers Choose Claude
Coding Supremacy:
Claude Opus 4.5 achieves 80.9% on SWE-bench Verified, surpassing both GPT-5.2 (74.9%) and Gemini 3 Pro (76.8%). It also leads on:
- Terminal-Bench Hard: 44% accuracy
- LiveCodeBench: +16 percentage points over Claude Sonnet 4.5
- MMLU-Pro: 90% (tied with Gemini 3 Pro)
Agentic Task Leadership:
Opus 4.5 excels at complex, multi-step workflows requiring planning and execution. Performance improvements over Sonnet 4.5 include:
- LiveCodeBench: +16 p.p.
- Terminal-Bench Hard: +11 p.p.
- Humanity's Last Exam: +11 p.p.
AI Safety Leadership:
- 4th-lowest hallucination rate (58%) among frontier models
- Ranks 2nd in AA-Omniscience Index (10/13)
- Constitutional AI framework ensures safer outputs
Massive Price Cut
Anthropic slashed pricing by 66% compared to Claude Opus 4.1:
- $5 per million input tokens
- $25 per million output tokens
This makes Opus 4.5 significantly more affordable than GPT-5.2 while delivering superior coding performance.
When to Choose Claude Opus 4.5
- Complex software engineering tasks
- Agentic workflows requiring multi-step planning
- Long-context reasoning (documentation analysis, code reviews)
- Applications prioritizing AI safety and reduced hallucinations
Gemini 3 Pro: Google's Multimodal Giant
Google's Gemini 3 Pro, released in November 2025, was designed for the "agentic era" with unprecedented multimodal capabilities.
Standout Features
Massive Context Window:
Gemini 3 Pro supports a 1 million token context window—2.5x larger than GPT-5.2's 400K tokens. This enables:
- Analysis of entire codebases at once
- Processing hours of video content
- Complex multi-document workflows
Native Multimodality:
Unlike GPT-5 and Claude, which bolt on vision capabilities, Gemini 3 Pro is natively multimodal from the ground up:
- Image generation
- Audio output
- Inputs: text, image, video, audio, PDF files
Built for Agentic AI:
Gemini 3 Pro can:
- Chain together multiple models
- Call external functions (send emails, process payments)
- Use tools like Google Search and Maps natively
- Think multiple steps ahead with supervised action-taking
Gemini Variants
Gemini 3 Pro: The flagship model for complex reasoning and multimodal tasks.
Gemini 2.0 Flash: A faster, more efficient variant achieving:
- 650ms average response time (fastest among frontier models)
- 79% coding accuracy
- Lower cost for high-volume applications
Performance Benchmarks
- SWE-bench Verified: 76.8% (3rd place behind Claude and GPT-5)
- MMLU-Pro: 90% (tied with Claude Opus 4.5)
- Context window: 1M tokens (largest available)
Pricing
Gemini pricing varies by variant and deployment method (Google AI Studio, Vertex AI). Flash variants offer significant cost savings for applications that don't require Pro-level reasoning.
Performance Benchmarks: Head-to-Head Comparison
Coding Performance
| Model | SWE-bench Verified | Terminal-Bench Hard | Overall Coding Accuracy |
|---|---|---|---|
| Claude Opus 4.5 | 80.9% | 44% | 96% |
| Gemini 3 Pro | 76.8% | - | - |
| GPT-5.2 | 74.9% | - | 94% |
Winner: Claude Opus 4.5 for professional software engineering
Reasoning & Knowledge
| Model | MMLU | GSM8K (Math) | GPQA Diamond |
|---|---|---|---|
| GPT-5.2 | 94.2% | 96.8% | 93.2% |
| Claude Opus 4.5 | 93.8% | 95.4% | - |
| Gemini 3 Pro | ~92% | - | - |
Winner: GPT-5.2 for pure reasoning tasks
Speed & Efficiency
| Model | Tokens/Second | Average Response Time |
|---|---|---|
| GPT-5.2 | 187 | Fast |
| Claude Opus 4.5 | ~50 | Slower |
| Gemini 2.0 Flash | - | 650ms (fastest) |
Winner: Gemini 2.0 Flash for latency-sensitive applications
Hallucination & Accuracy
| Model | Hallucination Rate | Data Retrieval Accuracy |
|---|---|---|
| GPT-5.2 | 4.8% | 98% (256K context) |
| Claude Opus 4.5 | 58% (low relative) | High |
| Gemini 3 Pro | Moderate | - |
Winner: GPT-5.2 for factual accuracy
Pricing Comparison
| Model | Input (per 1M tokens) | Output (per 1M tokens) | Value Proposition |
|---|---|---|---|
| GPT-5.2 | $20 | $60 | Premium reasoning + speed |
| Claude Opus 4.5 | $5 | $25 | Best coding at mid-tier price |
| Gemini 3 Pro | Varies | Varies | Flexible pricing tiers |
| DeepSeek V3.2 | $0.14 | - | Budget alternative (94% cheaper) |
Cost Winner: Claude Opus 4.5 offers the best performance-to-price ratio for most applications.
Best Use Cases: Which Model Should You Choose?
Choose GPT-5.2 If You Need:
- Real-time customer support requiring fast, accurate responses
- Advanced mathematics or scientific problem-solving
- Low hallucination rates for mission-critical applications
- Reasoning-heavy tasks like strategic planning or complex analysis
- MCP integrations with tools like Gmail and Google Calendar
Example Use Cases:
- Medical diagnosis assistance
- Financial analysis and forecasting
- Legal document analysis
- Complex SQL query generation
Choose Claude Opus 4.5 If You Need:
- Professional software engineering (debugging, code reviews, refactoring)
- Agentic workflows requiring multi-step planning
- AI safety and constitutional AI alignment
- Long-form content with consistent voice and reasoning
- Terminal automation and DevOps tasks
Example Use Cases:
- Full-stack application development (see our guide on best AI coding tools)
- Code migration projects
- Technical documentation writing
- Automated testing and CI/CD workflows
Choose Gemini 3 Pro If You Need:
- Massive context windows (analyzing entire codebases or hours of video)
- Native multimodal AI (combining text, image, audio, video)
- Agentic automation with Google Workspace integration
- Fast prototyping with Gemini 2.0 Flash
- Cost-effective scaling for high-volume applications
Example Use Cases:
- Video content analysis and summarization
- Multi-document research synthesis
- Creative multimodal projects (combining images, audio, text)
- Chrome browser automation (Project Mariner)
Budget-Conscious Alternative
DeepSeek V3.2 offers 94% cost savings at $0.14 per million tokens while maintaining 94% reasoning accuracy—ideal for startups and high-volume applications where cost is paramount.
Which Model Should You Choose?
The "best" AI model depends entirely on your specific needs:
For Most Developers: Start with Claude Opus 4.5. Its superior coding performance, reasonable pricing, and strong agentic capabilities make it the most versatile choice for technical work.
For Enterprise & Mission-Critical: Choose GPT-5.2. The lower hallucination rate, faster speed, and advanced reasoning justify the premium pricing for applications where accuracy matters most.
For Multimodal & Research: Pick Gemini 3 Pro. The massive context window and native multimodal capabilities are unmatched for complex analysis spanning multiple data types.
For Cost Optimization: Consider model routing—using GPT-5.2 for complex reasoning, Claude Opus 4.5 for coding, Gemini Flash for simple queries, and DeepSeek V3.2 for high-volume, cost-sensitive tasks. Learn more about running AI models locally to reduce costs further.
The Future: Model Routing & Specialization
Rather than choosing a single model, leading AI applications now use intelligent model routing to optimize for task requirements, cost, and latency. This approach:
- Routes simple queries to fast, cheap models (Gemini Flash, DeepSeek)
- Sends coding tasks to Claude Opus 4.5
- Uses GPT-5.2 for complex reasoning requiring low hallucinations
- Leverages Gemini 3 Pro for multimodal analysis
As we move through 2026, expect continued specialization where each model excels in its domain rather than attempting general-purpose dominance.
Frequently Asked Questions
Is GPT-5 better than GPT-4?
Yes, significantly. GPT-5.2 shows 65% fewer hallucinations, 20+ percentage point improvements on coding benchmarks, and 100% accuracy on AIME 2025 mathematics—a massive leap over GPT-4o's ~45%.
What's the main difference between Claude Opus 4.5 and Sonnet 4.5?
Opus 4.5 is Anthropic's flagship model optimized for maximum intelligence, scoring 70 in reasoning mode (+7 over Sonnet 4.5). It leads in coding (80.9% SWE-bench) and complex agentic tasks but costs more and runs slower than Sonnet, which is optimized for balanced performance and speed. Read our detailed comparison of Claude Sonnet 4.5 vs Opus 4.5 for more insights.
Can Gemini 3 Pro really handle 1 million tokens?
Yes. Gemini 3 Pro's 1M token context window enables analysis of entire codebases, hours of video, or hundreds of documents simultaneously—2.5x larger than GPT-5.2's 400K tokens.
Which model is best for coding?
Claude Opus 4.5 leads with 80.9% on SWE-bench Verified, followed by Gemini 3 Pro (76.8%) and GPT-5.2 (74.9%). For professional software engineering, Claude is the clear winner.
How much do these models cost?
- GPT-5.2: $20/$60 per million input/output tokens
- Claude Opus 4.5: $5/$25 per million (66% cheaper than predecessor)
- Gemini 3 Pro: Varies by deployment; Flash variants significantly cheaper
- DeepSeek V3.2: $0.14 per million (budget alternative)
Which model has the lowest hallucination rate?
GPT-5.2 at 4.8%, compared to GPT-4o's 11-15%. Claude Opus 4.5 maintains the 4th-lowest rate among frontier models at 58% (measured differently).
Can I use multiple models together?
Absolutely. Modern AI applications use model routing to leverage each model's strengths—GPT-5.2 for reasoning, Claude for coding, Gemini for multimodal tasks, and cheaper models for simple queries.
What is "agentic AI"?
Agentic AI refers to models that can plan multi-step workflows, call external tools, and take actions with supervision. Both Claude Opus 4.5 and Gemini 3 Pro excel at agentic tasks like automating complex workflows, writing and executing code, or managing multi-step projects. Explore our complete guide to AI agents to learn more.
The AI landscape in early 2026 offers unprecedented choice and capability. GPT-5.2 delivers unmatched reasoning and speed, Claude Opus 4.5 dominates coding and agentic workflows, while Gemini 3 Pro breaks new ground in multimodal intelligence and context length. For the latest developments, check our AI News & Trends January 2026 digest.
Rather than declaring a single winner, the smartest approach is understanding each model's strengths and routing tasks accordingly. For developers building production AI applications, investing in multi-model infrastructure will maximize both performance and cost-efficiency as these models continue evolving through 2026.
The bottom line: Start with Claude Opus 4.5 for its versatility and value, experiment with GPT-5.2 for critical reasoning tasks, and leverage Gemini 3 Pro when you need massive context or multimodal capabilities. The future of AI isn't about choosing one model—it's about orchestrating the right model for each task.
