GPT-5.1-Codex vs GPT-5.5 Pro
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.
GPT-5.1-Codex vs GPT-5.5 Pro: side by side
| Spec | GPT-5.1-Codex | GPT-5.5 Pro | Winner |
|---|---|---|---|
| Intelligence | 34.7 | — | Tie |
| Output speed | 169 t/s | — | Tie |
| Output price | $10.00/1M | $180.00/1M | GPT-5.1-Codex |
| Context | 400K | 1050K | GPT-5.5 Pro |
| Params | — | — | Tie |
| Provider | OpenAI | OpenAI | Tie |
GPT-5.1-Codex
Pros
- +Strong performance on extended coding workflows
- +Effective integration of visual context with code
- +Handles very large inputs without losing coherence
Cons
- –Limited to text and image inputs only
- –High computational cost for maximum context
- –May require careful prompt engineering for complex tasks
GPT-5.5 Pro
Pros
- +Very large context window
- +Native support for files, images, and text
- +Seamless multimodal integration
Cons
- –High resource use with maximum context
- –No audio or video modalities
- –Potential latency on very long inputs
Frequently asked questions
It depends on your needs. GPT-5.1-Codex and GPT-5.5 Pro are both multimodal models; the comparison table above shows where each one leads on the metrics that matter. See the verdict for a recommendation.