Anthropic: Claude Sonnet 4.5 vs OpenAI: GPT-5.3-Codex
Side-by-side comparison of Anthropic: Claude Sonnet 4.5 and OpenAI: GPT-5.3-Codex. Compare pricing, context window, capabilities, and find out which is better for your workflow.
Verdict
moderate confidenceOpenAI: GPT-5.3-Codex leads overall
OpenAI: GPT-5.3-Codex 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-5.3-Codex
Side-by-side
Technical specifications
| Anthropic: Claude Sonnet 4.5 | OpenAI: GPT-5.3-Codex | |
|---|---|---|
| Provider | Anthropic | OpenAI |
| Input price | $3/M | $2/M |
| Output price | $15/M | $14/M |
| Context window | 1.0M | 400K |
| Max output | 64K | 128K |
| Capabilities | Tool useVisionReasoning | Tool useVisionReasoning |
| Released | Sep 29, 2025 | Feb 24, 2026 |
Scoring breakdown
How each dimension compares
Price
OpenAI: GPT-5.3-Codex leadsAnthropic: Claude Sonnet 4.5
$15/M tokens
OpenAI: GPT-5.3-Codex
$14/M tokens
Context Window
Anthropic: Claude Sonnet 4.5 leadsAnthropic: Claude Sonnet 4.5
1.0M tokens
OpenAI: GPT-5.3-Codex
400K tokens
Capabilities
Anthropic: Claude Sonnet 4.5
3/4
OpenAI: GPT-5.3-Codex
3/4
Max Output
OpenAI: GPT-5.3-Codex leadsAnthropic: Claude Sonnet 4.5
64K tokens
OpenAI: GPT-5.3-Codex
128K tokens
Recency
Anthropic: Claude Sonnet 4.5
Sep 2025
OpenAI: GPT-5.3-Codex
Feb 2026
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