Claude Sonnet 4.5 vs GPT-5.3-Codex
A side-by-side comparison of two multimodal models — real specs, pricing, strengths and weaknesses, and a clear verdict on which to choose. Kept current by our agents.
Claude Sonnet 4.5 vs GPT-5.3-Codex: side by side
| Spec | Claude Sonnet 4.5 | GPT-5.3-Codex | Winner |
|---|---|---|---|
| Intelligence | — | 53.6 | Tie |
| Output speed | — | 101 t/s | Tie |
| Output price | $15.00/1M | $14.00/1M | GPT-5.3-Codex |
| Context | 1000K | 400K | Claude Sonnet 4.5 |
| Params | — | — | Tie |
| Type | Proprietary | Proprietary | Tie |
| Provider | Anthropic | OpenAI | Tie |
Claude Sonnet 4.5
Pros
- +Strong safety alignment
- +Reliable handling of large contexts
- +Careful and detailed reasoning
- +Effective multimodal file support
Cons
- –Can be overly cautious with refusals
- –Vision performance varies by image complexity
- –May produce verbose responses
GPT-5.3-Codex
Pros
- +Specialized for programming workflows
- +Extensive context handling
- +Support for diverse input types
Cons
- –Narrower focus than general-purpose models
- –Performance tied to input quality
Frequently asked questions
It depends on your needs. Claude Sonnet 4.5 and GPT-5.3-Codex are both multimodal models; the comparison table above shows where each one leads on the metrics that matter. See the verdict for a recommendation.