Claude Sonnet 4.5 vs Kimi K3
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 Kimi K3.
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...
Kimi K3
Kimi K3 is an ultra-large-scale, open-weight multimodal reasoning model from Moonshot AI. It is suited for complex coding, knowledge work, and long-horizon agentic workflows, and is particularly strong at navigating...
Technical Specifications
| Specification | Claude Sonnet 4.5 | Kimi K3 |
|---|---|---|
| Provider | Anthropic | Moonshot AI |
| Context Window | 1,000,000 tokens | 1,048,576 tokens |
| Agent Suitability | 91/100 | N/A |
| Time to First Token (TTFT) | 380 ms | N/A |
| Deployment Model | managed api | managed api |
| Production Stability | stable | beta |
| API Available | Yes | Yes |
| Released Date | 2025-09-29 | 2026-07-16 |
API Pricing Comparison
Input Price per Million Tokens
Claude Sonnet 4.5
$3.00
Kimi K3
$3.00
Output Price per Million Tokens
Claude Sonnet 4.5
$15.00
Kimi K3
$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 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
Kimi K3 Quirks & Gotchas
No developer gotchas reported.