Claude Sonnet 4.5 vs GLM 5.1
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 GLM 5.1.
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...
GLM 5.1
GLM-5.1 delivers a major leap in coding capability, with particularly significant gains in handling long-horizon tasks. Unlike previous models built around minute-level interactions, GLM-5.1 can work independently and continuously on...
Technical Specifications
| Specification | Claude Sonnet 4.5 | GLM 5.1 |
|---|---|---|
| Provider | Anthropic | Zhipu AI |
| Context Window | 1,000,000 tokens | 202,752 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 | 2026-04-07 |
API Pricing Comparison
Input Price per Million Tokens
Claude Sonnet 4.5
$3.00
GLM 5.1
$0.97
Output Price per Million Tokens
Claude Sonnet 4.5
$15.00
GLM 5.1
$3.04
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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
GLM 5.1 Quirks & Gotchas
No developer gotchas reported.