Claude Opus 4.5 vs o3 Mini
How do these models stack up? Below is an expert side-by-side comparison of specifications, context window capacity, live pricing per million tokens, and standardized benchmark scores for Claude Opus 4.5 and o3 Mini.
Claude Opus 4.5
Claude Opus 4.5 is Anthropic’s frontier reasoning model optimized for complex software engineering, agentic workflows, and long-horizon computer use. It offers strong multimodal capabilities, competitive performance across real-world coding and...
o3 Mini
OpenAI o3-mini is a cost-efficient language model optimized for STEM reasoning tasks, particularly excelling in science, mathematics, and coding. This model supports the `reasoning_effort` parameter, which can be set to...
Technical Specifications
| Specification | Claude Opus 4.5 | o3 Mini |
|---|---|---|
| Provider | Anthropic | OpenAI |
| Context Window | 200,000 tokens | 200,000 tokens |
| Agent Suitability | 93/100 | 91/100 |
| Time to First Token (TTFT) | 550 ms | 800 ms |
| Deployment Model | managed api | managed api |
| Production Stability | stable | stable |
| API Available | Yes | Yes |
| Released Date | 2025-11-24 | 2025-01-31 |
API Pricing Comparison
Input Price per Million Tokens
Claude Opus 4.5
$5.00
o3 Mini
$1.10
Output Price per Million Tokens
Claude Opus 4.5
$25.00
o3 Mini
$4.40
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Benchmark Performance Metrics
Scores show the raw performance percentages verified across key evaluation suites. Higher bars indicate superior accuracy and capability in that domain.
Claude Opus 4.5 Quirks & Gotchas
- ▸Deep analytical reasoning — best for structured problem-solving
- ▸200K context is limiting compared to 1M of Opus 4.6+ — upgrade for long-document tasks
o3 Mini Quirks & Gotchas
- ▸Best cost/performance ratio for reasoning tasks in the OpenAI lineup
- ▸Still slower than GPT-5 for simple tool calls — route accordingly