Claude 3 Sonnet vs GPT-5.5 Pro
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 3 Sonnet and GPT-5.5 Pro.
Claude 3 Sonnet
Claude 3 Sonnet was Anthropic's balanced standard model in the first Claude 3 generation, optimized for a combination of response speed and general-purpose capabilities across writing, summarization, and question answering. Released in March 2024 alongside Opus and Haiku, it occupied the mid-tier positioning in the Claude 3 lineup. Claude 3 Sonnet has since been deprecated, and current use cases requiring similar capability-to-cost balance are best served by the Claude 4 Sonnet series, which offers substantially improved reasoning, context handling, and instruction following at competitive pricing.
GPT-5.5 Pro
GPT-5.5 Pro is OpenAI’s high-capability model optimized for deep reasoning and accuracy on complex, high-stakes workloads. It features a 1M+ token context window (922K input, 128K output) with support for...
Technical Specifications
| Specification | Claude 3 Sonnet | GPT-5.5 Pro |
|---|---|---|
| Provider | Anthropic | OpenAI |
| Context Window | 200,000 tokens | 1,050,000 tokens |
| Agent Suitability | N/A | 98/100 |
| Time to First Token (TTFT) | N/A | 450 ms |
| Deployment Model | N/A | managed api |
| Production Stability | stable | beta |
| API Available | Yes | Yes |
| Released Date | 2024-03-04 | 2026-04-24 |
API Pricing Comparison
Input Price per Million Tokens
Claude 3 Sonnet
$3.00
GPT-5.5 Pro
$30.00
Output Price per Million Tokens
Claude 3 Sonnet
$15.00
GPT-5.5 Pro
$180.00
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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 3 Sonnet Quirks & Gotchas
No developer gotchas reported.
GPT-5.5 Pro Quirks & Gotchas
- ▸Best-in-class instruction following for complex agentic chains
- ▸Premium pricing — use GPT-5 for cost-sensitive workloads