GPT-5.1 vs GPT-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.
Quick verdict: which should you choose?
Choose GPT-5.1 if you need
- ✓Choose GPT-5.1 if you need a known intelligence_index of 27.4 and output speed of 115.83 t/s.
- ✓Choose GPT-5.1 if you need the lower output price of $10 per 1M tokens.
- ✓Choose GPT-5.1 if you need native support for images, text, and files with strong multimodal integration.
- ✓Choose GPT-5.1 if you need a very large 400000 context window at lower cost.
Choose GPT-5 Pro if you need
- ✓Choose GPT-5 Pro if you need flexible reasoning over extended context in document-heavy workflows.
- ✓Choose GPT-5 Pro if you need strong integration of text, image, and file data for large inputs.
- ✓Choose GPT-5 Pro if you need handling of very large multimodal inputs despite higher cost.
Verdict
GPT-5.1 leads on verified metrics with a known intelligence_index of 27.4, output speed of 115.83 t/s, and $10/1M pricing while sharing the same 400k context and multimodal image/text/file support as GPT-5 Pro. GPT-5 Pro offers comparable strengths in large-input integration and document workflows but at a much higher $120/1M cost with unknown speed and intelligence scores. GPT-5.1 provides clearer performance transparency for most multimodal tasks.
GPT-5.1 vs GPT-5 Pro: side by side
| Spec | GPT-5.1 | GPT-5 Pro | Winner |
|---|---|---|---|
| Intelligence | 27.4 | — | Tie |
| Output speed | 116 t/s | — | Tie |
| Output price | $10.00/1M | $120.00/1M | GPT-5.1 |
| Context | 400K | 400K | Tie |
| Params | — | — | Tie |
| Type | Proprietary | Proprietary | Tie |
| Provider | OpenAI | OpenAI | Tie |
Detailed analysis
Pricing
Winner: GPT-5.1GPT-5.1 is listed at $10 per 1M output tokens while GPT-5 Pro is listed at $120 per 1M. Both are proprietary OpenAI models with identical 400000 context. The tenfold price difference favors GPT-5.1 for cost-sensitive multimodal use.
Speed & Intelligence
Winner: GPT-5.1GPT-5.1 provides concrete values of 115.83 t/s output speed and 27.4 intelligence_index. GPT-5 Pro lists neither metric. Both share the same context size and multimodal modalities, making GPT-5.1 the only option with verifiable performance data.
Context & Modalities
Winner: TieBoth models offer 400000 context and native support for images, text, and files. Neither supports audio or video. Strengths for large-input handling and multimodal integration are described similarly for both.
Workflow Suitability
Winner: TieGPT-5.1 emphasizes strong multimodal integration while GPT-5 Pro highlights suitability for document-heavy workflows and flexible reasoning. Both note potential issues with maximum context usage but provide no differentiating verified metrics.
GPT-5.1
Pros
- +Very large context window
- +Native support for images, text, and files
- +Strong multimodal integration
Cons
- –No audio or video modalities
- –Performance details unverified beyond specs
- –Potential latency with maximum context
GPT-5 Pro
Pros
- +Handles very large inputs across modalities
- +Strong integration of text, image, and file data
- +Suitable for document-heavy workflows
- +Flexible reasoning over extended context
Cons
- –No native real-time information access
- –Performance can vary on highly specialized topics
- –Higher computational cost with maximum context
Summary: GPT-5.1 vs GPT-5 Pro
Select GPT-5.1 when verified speed, intelligence score, and lower price matter for image/text/file tasks. Choose GPT-5 Pro only if its positioning for document workflows justifies the substantially higher cost despite missing performance data. Both share identical context and core multimodal capabilities from the same provider.
Frequently asked questions
GPT-5.1 is better on all verifiable metrics including intelligence_index, speed, and price while matching GPT-5 Pro on context and modalities.