Claude 3 Sonnet vs Claude Sonnet 4.5
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 Claude Sonnet 4.5.
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.
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...
Technical Specifications
| Specification | Claude 3 Sonnet | Claude Sonnet 4.5 |
|---|---|---|
| Provider | Anthropic | Anthropic |
| Context Window | 200,000 tokens | 1,000,000 tokens |
| Agent Suitability | N/A | 91/100 |
| Time to First Token (TTFT) | N/A | 380 ms |
| Deployment Model | N/A | managed api |
| Production Stability | stable | stable |
| API Available | Yes | Yes |
| Released Date | 2024-03-04 | 2025-09-29 |
API Pricing Comparison
Input Price per Million Tokens
Claude 3 Sonnet
$3.00
Claude Sonnet 4.5
$3.00
Output Price per Million Tokens
Claude 3 Sonnet
$15.00
Claude Sonnet 4.5
$15.00
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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.
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