GPT-5.1 vs Grok 4.3
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
- ✓complex multi-step reasoning with highest intelligence scores
- ✓maximum context (1M tokens) for document-level tasks at lowest cost
- ✓fastest output speed (134.99 t/s) combined with real-time tool access
- ✓budget-conscious deployments where price per million tokens matters
Choose Grok 4.3 if you need
- ✓native support for images, text, and files with strong multimodal integration
- ✓very large context window focused on unified file processing
- ✓scenarios where OpenAI's multimodal ecosystem is already in use
- ✓tasks prioritizing seamless cross-modal handling over raw speed or price
Verdict
Grok 4.3 leads on intelligence (43.9 vs 27.4), speed (134.99 t/s vs 115.83 t/s), price ($2.5 vs $10 per 1M tokens), and context size (1M vs 400k tokens), making it stronger for complex reasoning and large-document tasks. GPT-5.1 counters with native multimodal integration for images, text, and files plus a very large context window. Overall, Grok 4.3 wins on measurable performance and cost metrics while GPT-5.1 holds an edge in unified multimodal handling.
GPT-5.1 vs Grok 4.3: side by side
| Spec | GPT-5.1 | Grok 4.3 | Winner |
|---|---|---|---|
| Intelligence | 27.4 | 43.9 | Grok 4.3 |
| Output speed | 116 t/s | 135 t/s | Grok 4.3 |
| Output price | $10.00/1M | $2.50/1M | Grok 4.3 |
| Context | 400K | 1000K | Grok 4.3 |
| Params | — | — | Tie |
| Type | Proprietary | Proprietary | Tie |
| Provider | OpenAI | xAI | Tie |
Detailed analysis
Intelligence
Winner: Grok 4.3Grok 4.3 scores 43.9 on the intelligence index compared to GPT-5.1's 27.4. Its listed strengths explicitly include strong performance on complex multi-step reasoning. GPT-5.1's performance details remain unverified beyond specs.
Speed & Cost
Winner: Grok 4.3Grok 4.3 delivers higher output speed at 134.99 t/s versus 115.83 t/s and costs $2.5 per million tokens versus $10. These advantages hold across all listed metrics with no conflicting data.
Context Window
Winner: Grok 4.3Grok 4.3 provides a 1M-token context versus GPT-5.1's 400k tokens. Both models highlight large context as a strength, but Grok 4.3's window is more than double the size for document-level work.
Multimodal Integration
Winner: GPT-5.1GPT-5.1 lists native support for images, text, and files with strong multimodal integration. Grok 4.3 notes vision capabilities that are less mature than specialized models despite its multimodal designation.
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
Grok 4.3
Pros
- +Strong performance on complex multi-step reasoning
- +Large context window for document-level tasks
- +Helpful and direct response style
- +Integrated real-time tool access
Cons
- –Vision capabilities less mature than specialized models
- –Occasional over-refusal on edge-case queries
- –High computational cost for maximum context usage
Summary: GPT-5.1 vs Grok 4.3
Select Grok 4.3 when intelligence, speed, price, and maximum context are priorities. Choose GPT-5.1 when native multimodal file handling and OpenAI ecosystem compatibility outweigh the gaps in measured performance and cost.
Frequently asked questions
Grok 4.3 is better on intelligence, speed, price, and context size; GPT-5.1 is better on native multimodal integration.