Claude Sonnet 4.5 vs Gemini 3.1 Flash
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 Gemini 3.1 Flash.
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...
Gemini 3.1 Flash
Gemini 3.1 Flash is Google's high-speed, cost-efficient multimodal model in the 3.1 generation, purpose-built for high-volume content synthesis, classification, and intelligent routing at scale. Featuring a 1-million-token context window, it can process large batches of documents, customer data, or multimedia content in a single inference pass, dramatically reducing pipeline complexity. At just $0.25/MTok for input, it is one of the most affordable routes to Google-caliber multimodal AI, making it an ideal backbone for production pipelines, data enrichment workflows, and high-frequency API integrations.
Technical Specifications
| Specification | Claude Sonnet 4.5 | Gemini 3.1 Flash |
|---|---|---|
| Provider | Anthropic | |
| Context Window | 1,000,000 tokens | 1,000,000 tokens |
| Agent Suitability | 91/100 | 86/100 |
| Time to First Token (TTFT) | 380 ms | 150 ms |
| Deployment Model | managed api | managed api |
| Production Stability | stable | stable |
| API Available | Yes | Yes |
| Released Date | 2025-09-29 | 2026-04-20 |
API Pricing Comparison
Input Price per Million Tokens
Claude Sonnet 4.5
$3.00
Gemini 3.1 Flash
$0.25
Output Price per Million Tokens
Claude Sonnet 4.5
$15.00
Gemini 3.1 Flash
$1.50
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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 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
Gemini 3.1 Flash Quirks & Gotchas
- ▸Most cost-effective Google model — ideal for high-volume pipelines
- ▸Context caching available via Vertex AI for repeated document processing