xAI has launched a newer model, Grok 4.20 Beta 0309, we suggest considering this model instead.
For more information, see Comparison of Grok 4.20 Beta 0309 to other models and API provider benchmarks for Grok 4.20 Beta 0309.
Grok 4.1 Fast (Reasoning) Intelligence, Performance & Price Analysis
Model summary
Intelligence
Artificial Analysis Intelligence Index
Speed
Output tokens per second
Input Price
USD per 1M tokens
Output Price
USD per 1M tokens
Verbosity
Output tokens from Intelligence Index
Metrics are compared against models of the same class:
- Non-reasoning models → compared only with other non-reasoning models
- Reasoning models → compared across both reasoning and non-reasoning
- Open weights models → compared only with other open weights models of the same size class:
- Tiny: ≤4B parameters
- Small: 4B–40B parameters
- Medium: 40B–150B parameters
- Large: >150B parameters
- Proprietary models → compared across proprietary and open weights models of the same price range, using a blended 3:1 input/output price ratio:
- <$0.15 per 1M tokens
- $0.15–$1 per 1M tokens
- >$1 per 1M tokens
| Reasoning | Yes This page shows the reasoning version of this model. A non-reasoning variant may also exist. |
|---|---|
| Input modality | Supports: text, image |
| Output modality | Supports: text |
| Context window | 2m ~3000 A4 pages of size 12 Arial font |
Grok 4.1 Fast (Reasoning) is amongst the leading models in intelligence and reasonably priced when comparing to other models of similar price. It's also faster than average, however somewhat verbose. The model supports text and image input, outputs text, and has a 2m tokens context window.
Grok 4.1 Fast (Reasoning) scores 39 on the Artificial Analysis Intelligence Index, placing it well above average among comparable models (averaging 19). When evaluating the Intelligence Index, it generated 53M tokens, which is somewhat verbose in comparison to the average of 20M.
Pricing for Grok 4.1 Fast (Reasoning) is $0.20 per 1M input tokens (moderately priced, average: $0.25) and $0.50 per 1M output tokens (competitively priced, average: $0.90). In total, it cost $39.62 to evaluate Grok 4.1 Fast (Reasoning) on the Intelligence Index.
At 158 tokens per second, Grok 4.1 Fast (Reasoning) is faster than average (105).
Intelligence
Artificial Analysis Intelligence Index
Artificial Analysis Intelligence Index by Open Weights / Proprietary
Intelligence Evaluations
Openness
Artificial Analysis Openness Index: Results
Intelligence Index Comparisons
Intelligence vs. Price
Intelligence Index Token Use & Cost
Output Tokens Used to Run Artificial Analysis Intelligence Index
Cost to Run Artificial Analysis Intelligence Index
Context Window
Context Window
Pricing
Pricing: Input and Output Prices
Intelligence vs. Price (Log Scale)
Pricing Comparison of Grok 4.1 Fast (Reasoning) API Providers
Speed
Measured by Output Speed (tokens per second)
Output Speed
Output Speed vs. Price
Latency
Measured by Time (seconds) to First Token
Latency: Time To First Answer Token
End-to-End Response Time
Seconds to output 500 Tokens, calculated based on time to first token, 'thinking' time for reasoning models, and output speed
End-to-End Response Time
Model Size (Open Weights Models Only)
Model Size: Total and Active Parameters
Frequently Asked Questions
Common questions about Grok 4.1 Fast (Reasoning)
Grok 4.1 Fast (Reasoning) was released on November 19, 2025.
Grok 4.1 Fast (Reasoning) was created by xAI.
Grok 4.1 Fast (Reasoning) scores 39 on the Artificial Analysis Intelligence Index, placing it well above average among other reasoning models in a similar price tier (median: 19).
Grok 4.1 Fast (Reasoning) generates output at 157.7 tokens per second (based on xAI's API), which is above average compared to other reasoning models in a similar price tier (median: 105.3 t/s).
Grok 4.1 Fast (Reasoning) has a time to first token (TTFT) of 7.96s (based on xAI's API), which is at the higher end compared to other reasoning models in a similar price tier (median: 1.82s).
Grok 4.1 Fast (Reasoning) costs $0.20 per 1M input tokens (better than average, median: $0.25) and $0.50 per 1M output tokens (very competitive, median: $0.90), based on xAI's API.
Grok 4.1 Fast (Reasoning) costs $0.20 per 1M input tokens and $0.50 per 1M output tokens (based on xAI's API). For a blended rate (3:1 input to output ratio), this is $0.28 per 1M tokens. Pricing may vary by provider. Compare provider pricing
When evaluated on the Intelligence Index, Grok 4.1 Fast (Reasoning) generated 53M output tokens, which is somewhat higher than average compared to other reasoning models in a similar price tier (median: 20M).
Yes, Grok 4.1 Fast (Reasoning) is a reasoning model. It uses extended thinking or chain-of-thought reasoning to work through complex problems before providing an answer.
Grok 4.1 Fast (Reasoning) supports text and image input.
Grok 4.1 Fast (Reasoning) supports text output.
Yes, Grok 4.1 Fast (Reasoning) supports image input and can analyze, describe, and answer questions about images.
Yes, Grok 4.1 Fast (Reasoning) is multimodal. It can process text and image input and generate text output.
Grok 4.1 Fast (Reasoning) has a context window of 2.0M tokens. This determines how much text and conversation history the model can process in a single request.
No, Grok 4.1 Fast (Reasoning) is proprietary. The model weights are not publicly available.
Grok 4.1 Fast (Reasoning) is a proprietary model and xAI has not disclosed the model size or parameter count.
Grok 4.1 Fast (Reasoning) achieves a score of 39 on the Artificial Analysis Intelligence Index. This composite benchmark evaluates models across reasoning, knowledge, mathematics, and coding.
Yes, Grok 4.1 Fast (Reasoning) is available via API through 1 provider. Compare API providers
Grok 4.1 Fast (Reasoning) is available through 1 API provider. Compare providers