GPT-5.2 and Claude Opus 4.5 are the two most capable AI models from OpenAI and Anthropic. Both are flagship products representing billions in research investment. But they excel at different things.
Here's everything you need to know to choose between them - or use both.
Quick Comparison
| Specification | GPT-5.2 | Claude Opus 4.5 |
|---|---|---|
| Provider | OpenAI | Anthropic |
| Context Window | 400K tokens | 200K tokens |
| Output Tokens | 128K | 8K |
| ARC-AGI-1 | 90%+ (first ever) | Not reported |
| AIME 2025 Math | 100% | Not reported |
| SWE-Bench Verified | ~75% | 81% |
| SWE-Bench Pro | 55.6% | Not reported |
| Thinking Mode | Yes (Thinking variant) | Yes (effort parameter) |
| Speed | Fast (Instant mode) | Slower |
GPT-5.2 Overview
Released December 11, 2025, GPT-5.2 is OpenAI's most advanced model. It's the first model to score above 90% on ARC-AGI-1 and achieves 100% on AIME 2025 math benchmarks.
Key Strengths
- Reasoning Excellence - First model to break 90% on ARC-AGI, the benchmark designed to test general reasoning
- Mathematical Mastery - Perfect 100% score on AIME 2025 mathematical reasoning
- Large Context - 400K token input allows processing entire codebases
- Speed Options - Instant mode for quick tasks, Thinking mode for complex reasoning, Pro mode for accuracy
- 55.6% SWE-Bench Pro - Strong agentic coding performance
Variants Available
- GPT-5.2 (Instant) - Fast responses for everyday tasks
- GPT-5.2 (Thinking) - Deeper reasoning with thinking tokens
- GPT-5.2 Pro - Maximum accuracy for difficult questions
Claude Opus 4.5 Overview
Released November 2025, Claude Opus 4.5 is Anthropic's most capable model. It leads on SWE-bench Verified and offers unique features like the effort parameter for controlling reasoning depth.
Key Strengths
- Coding Excellence - 81% on SWE-bench Verified, state-of-the-art for coding tasks
- Effort Parameter - Unique ability to control how much "thinking" the model does
- Fewer Tool Errors - 50-75% reduction in tool calling errors compared to competitors
- Quality Writing - Known for nuanced, well-structured prose
- Strong Instruction Following - Excels at complex multi-step tasks
Unique Features
- Effort Parameter - Control reasoning depth per request
- Extended Thinking - Preserved across multi-turn conversations
- 15% Better Than Sonnet - On Terminal Bench complex tasks
Head-to-Head: Where Each Excels
Reasoning & Problem Solving
Winner: GPT-5.2
GPT-5.2's ARC-AGI score of 90%+ is unprecedented. The model also achieves 100% on AIME 2025, showing mathematical reasoning mastery. For pure reasoning tasks, GPT-5.2 currently leads.
Coding & Development
Winner: Claude Opus 4.5
Claude Opus 4.5 leads on SWE-bench Verified (81%), the standard benchmark for real-world coding ability. It also shows 50-75% fewer tool calling errors, which matters for agentic coding workflows. For day-to-day coding assistance, Opus has the edge.
Context Window & Memory
Winner: GPT-5.2
GPT-5.2's 400K context window is twice the size of Opus's 200K. For processing large codebases, long documents, or extended conversations, GPT-5.2 can handle more information at once.
Speed & Efficiency
Winner: GPT-5.2
GPT-5.2's Instant mode provides fast responses for everyday tasks. Opus 4.5 is categorized as "slow" - it prioritizes quality over speed. If you need quick answers, GPT-5.2 is faster.
Writing Quality
Winner: Claude Opus 4.5
Claude models are known for nuanced, well-structured writing. Opus 4.5 excels at long-form content, creative writing, and maintaining consistent tone across documents.
Pricing
Subscription Pricing
ChatGPT Plus: $20/month - GPT-5.2 access
Claude Pro: $20/month - Opus 4.5 access
Go Ask Chat Pro: $8/month - Both GPT-5.2 AND Opus 4.5 + 26 more models
Both ChatGPT Plus and Claude Pro cost $20/month for access to a single AI family. Go Ask Chat gives you both for $8/month.
Which Should You Choose?
Choose GPT-5.2 if you need:
- Complex mathematical reasoning (100% AIME)
- General reasoning tasks (90%+ ARC-AGI)
- Large context processing (400K tokens)
- Fast responses (Instant mode)
Choose Claude Opus 4.5 if you need:
- Production coding assistance (81% SWE-bench)
- Fewer tool/API errors (50-75% reduction)
- High-quality writing
- Fine-grained reasoning control (effort parameter)
Why Not Both?
The reality is that GPT-5.2 and Claude Opus 4.5 complement each other. GPT excels at reasoning and math. Claude excels at coding and writing. The best approach is to use both depending on the task.
With Go Ask Chat, you can switch between GPT-5.2 and Claude Opus mid-conversation. Start with GPT for reasoning, switch to Claude for implementation. One subscription, all models.
Use Both for $8/month
Get GPT-5.2, Claude Opus 4.5, and 26 more models. No separate subscriptions.
Try Free - 20 Messages/DayFrequently Asked Questions
Is GPT-5.2 better than Claude Opus 4.5?
Neither is universally "better." GPT-5.2 leads on reasoning benchmarks (ARC-AGI, AIME). Claude Opus 4.5 leads on coding benchmarks (SWE-bench). The best model depends on your specific task.
Which is better for coding?
Claude Opus 4.5 edges out GPT-5.2 on SWE-bench Verified (81% vs ~75%) and has fewer tool calling errors. For production coding work, Opus has a slight advantage. However, GPT-5.2's larger context window (400K vs 200K) can be helpful for large codebases.
Which is faster?
GPT-5.2 in Instant mode is faster than Claude Opus 4.5. Opus prioritizes quality over speed.
Can I use both in Go Ask Chat?
Yes. Go Ask Chat includes both GPT-5.2 and Claude Opus 4.5, plus Sonnet, Haiku, and 24 more models. Switch between them mid-conversation with one click.