GPT-5.1-Codex vs GPT-5.5
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: side by side
| Spec | GPT-5.1-Codex | GPT-5.5 | Winner |
|---|---|---|---|
| Intelligence | 43.1 | 50.8 | GPT-5.5 |
| Output speed | 178 t/s | 60 t/s | GPT-5.1-Codex |
| Output price | $10.00/1M | $30.00/1M | GPT-5.1-Codex |
| Context | 400K | 1050K | GPT-5.5 |
| Params | — | — | Tie |
| Type | Proprietary | Proprietary | 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
- +Specialized for software development tasks
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
Pros
- +Extremely large context window
- +Native support for files and images
- +Flexible multimodal workflows
- +Suitable for document-heavy tasks
Cons
- –No native audio or video support
- –Large context may increase latency
- –Performance depends on input quality across modalities
Frequently asked questions
It depends on your needs. GPT-5.1-Codex and GPT-5.5 are both multimodal models; the comparison table above shows where each one leads on the metrics that matter. See the verdict for a recommendation.