GPT-5 Nano 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 Nano if you need
- ✓Complex multi-step reasoning with its 35.4 intelligence index
- ✓Maximum 1M-token context for document-level tasks
- ✓Integrated real-time tool access and direct response style
- ✓Scenarios where higher capability depth outweighs cost
Choose Grok 4.3 if you need
- ✓Faster responses at 162.11 t/s output speed
- ✓Lowest cost at $0.4 per 1M tokens for high-volume use
- ✓Efficient handling of text, image, and file inputs together
- ✓Lightweight extended document tasks without maximum complexity
Verdict
Grok 4.3 leads in intelligence and context size for complex multi-step reasoning and document tasks, while GPT-5 Nano leads in speed and price with efficient handling of text, image, and file inputs. Grok's 35.4 intelligence index and 1M context outperform GPT-5 Nano's 19.9 index and 400k context, but at over six times the cost and lower speed. GPT-5 Nano is the practical choice for lightweight, high-volume use cases.
GPT-5 Nano vs Grok 4.3: side by side
| Spec | GPT-5 Nano | Grok 4.3 | Winner |
|---|---|---|---|
| Intelligence | 19.9 | 35.4 | Grok 4.3 |
| Output speed | 162 t/s | 136 t/s | GPT-5 Nano |
| Output price | $0.40/1M | $2.50/1M | GPT-5 Nano |
| Context | 400K | 1000K | Grok 4.3 |
| Params | — | — | Tie |
| Provider | OpenAI | xAI | Tie |
Detailed analysis
Intelligence
Winner: Grok 4.3Grok 4.3 scores 35.4 on the intelligence index versus GPT-5 Nano's 19.9, aligning with its listed strengths in complex multi-step reasoning. GPT-5 Nano's lower score matches its noted limitations in capability depth and complex reasoning tasks.
Speed
Winner: GPT-5 NanoGPT-5 Nano delivers 162.11 tokens per second compared to Grok 4.3's 135.7 t/s, consistent with its lightweight design for faster responses. Grok 4.3 shows no speed advantage in the provided metrics.
Pricing
Winner: GPT-5 NanoGPT-5 Nano costs $0.4 per 1M tokens while Grok 4.3 costs $2.5 per 1M, a more than sixfold difference. This price gap directly supports GPT-5 Nano for cost-sensitive or high-volume workloads.
Context
Winner: Grok 4.3Grok 4.3 provides a 1M-token context window versus GPT-5 Nano's 400k, enabling stronger performance on large document-level tasks. Both handle extended contexts but Grok's size is double that of GPT-5 Nano.
GPT-5 Nano
Pros
- +Handles very large contexts efficiently
- +Supports text, image, and file inputs
- +Lightweight design for faster responses
Cons
- –Lower capability depth than full-scale models
- –May struggle with highly complex reasoning
- –Trade-off in advanced task performance
Grok 4.3
Pros
- +Strong performance on complex multi-step reasoning
- +Large context window for document-level tasks
- +Helpful and direct response style
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 Nano vs Grok 4.3
Choose Grok 4.3 when intelligence, maximum context, and complex reasoning are priorities despite higher cost. Select GPT-5 Nano for speed, affordability, and practical multimodal file handling in less demanding scenarios. The data shows a clear capability-versus-efficiency trade-off between the two models.
Frequently asked questions
Grok 4.3 is stronger for complex reasoning and large contexts while GPT-5 Nano is better for speed and cost efficiency; neither dominates all multimodal use cases.