Anthropic: Claude Sonnet 4.5 vs OpenAI: GPT-5.1-Codex-Max
Side-by-side comparison of Anthropic: Claude Sonnet 4.5 and OpenAI: GPT-5.1-Codex-Max. Compare pricing, context window, capabilities, and find out which is better for your workflow.
Verdict
strong confidenceOpenAI: GPT-5.1-Codex-Max leads overall
OpenAI: GPT-5.1-Codex-Max leads in price and max output, making it the stronger choice for most workflows. Anthropic: Claude Sonnet 4.5 remains competitive with advantages in context window.
Best for with Anthropic: Claude Sonnet 4.5
Best for with OpenAI: GPT-5.1-Codex-Max
Side-by-side
Technical specifications
| Anthropic: Claude Sonnet 4.5 | OpenAI: GPT-5.1-Codex-Max | |
|---|---|---|
| Provider | Anthropic | OpenAI |
| Input price | $3/M | $1/M |
| Output price | $15/M | $10/M |
| Context window | 1.0M | 400K |
| Max output | 64K | 128K |
| Capabilities | Tool useVisionReasoning | Tool useVisionReasoning |
| Released | Sep 29, 2025 | Dec 4, 2025 |
Scoring breakdown
How each dimension compares
Price
OpenAI: GPT-5.1-Codex-Max leadsAnthropic: Claude Sonnet 4.5
$15/M tokens
OpenAI: GPT-5.1-Codex-Max
$10/M tokens
Context Window
Anthropic: Claude Sonnet 4.5 leadsAnthropic: Claude Sonnet 4.5
1.0M tokens
OpenAI: GPT-5.1-Codex-Max
400K tokens
Capabilities
Anthropic: Claude Sonnet 4.5
3/4
OpenAI: GPT-5.1-Codex-Max
3/4
Max Output
OpenAI: GPT-5.1-Codex-Max leadsAnthropic: Claude Sonnet 4.5
64K tokens
OpenAI: GPT-5.1-Codex-Max
128K tokens
Recency
Anthropic: Claude Sonnet 4.5
Sep 2025
OpenAI: GPT-5.1-Codex-Max
Dec 2025
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