Claude Sonnet 4.5 vs Kimi K2 Thinking
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 K2 Thinking.
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 K2 Thinking
Kimi K2 Thinking is Moonshot AI’s most advanced open reasoning model to date, extending the K2 series into agentic, long-horizon reasoning. Built on the trillion-parameter Mixture-of-Experts (MoE) architecture introduced in...
Technical Specifications
| Specification | Claude Sonnet 4.5 | Kimi K2 Thinking |
|---|---|---|
| Provider | Anthropic | Moonshot AI |
| Context Window | 1,000,000 tokens | 262,144 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 | stable |
| API Available | Yes | Yes |
| Released Date | 2025-09-29 | 2025-11-06 |
API Pricing Comparison
Input Price per Million Tokens
Claude Sonnet 4.5
$3.00
Kimi K2 Thinking
$0.60
Output Price per Million Tokens
Claude Sonnet 4.5
$15.00
Kimi K2 Thinking
$2.50
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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
Kimi K2 Thinking Quirks & Gotchas
No developer gotchas reported.