Claude Sonnet 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 Sonnet 4.5 and o3 Mini.
Claude Sonnet 4.5
Claude Sonnet 4.5 is Anthropic’s most advanced Sonnet model to date, optimized for real-world agents and coding workflows. It delivers state-of-the-art performance on coding benchmarks such as SWE-bench Verified, with...
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 Sonnet 4.5 | o3 Mini |
|---|---|---|
| Provider | Anthropic | OpenAI |
| Context Window | 1,000,000 tokens | 200,000 tokens |
| Agent Suitability | 91/100 | 91/100 |
| Time to First Token (TTFT) | 380 ms | 800 ms |
| Deployment Model | managed api | managed api |
| Production Stability | stable | stable |
| API Available | Yes | Yes |
| Released Date | 2025-09-29 | 2025-01-31 |
API Pricing Comparison
Input Price per Million Tokens
Claude Sonnet 4.5
$3.00
o3 Mini
$1.10
Output Price per Million Tokens
Claude Sonnet 4.5
$15.00
o3 Mini
$4.40
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Run side-by-side prompt prompts in our dynamic Sandbox. Check execution speeds, latency metrics, and compute actual costs in real-time.
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 Sonnet 4.5 Quirks & Gotchas
- ▸Excellent for long-form writing and nuanced document analysis
- ▸Slightly slower than Sonnet 4.6 — upgrade for production agentic use
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