Model Library
xAIReleased September 19, 2025Grok 4 Fast
xAI · Released September 19, 2025
Intelligence score
27
At a glance
- Intelligence
- 27
- Speed
- —
- Latency
- —
- Input price
- $0.20per 1M tokens
- Output price
- $0.50per 1M tokens
- Context window
- 4tokens
- Parameters
- —
Summary
Comparison summary
Grok 4 Fast (Reasoning) scores 27 (estimated) on the Artificial Analysis Intelligence Index, placing it well above average among other reasoning models in a similar price tier (median: 15). Grok 4 Fast (Reasoning) costs $0.20 per 1M input tokens (better than average, median: $0.25) and $0.50 per 1M output tokens (better than average, median: $0.87), based on the median across providers serving the model.
Specifications
Technical specifications
| Model name | Grok 4 Fast |
|---|---|
| Provider | xAI |
| Release date | September 19, 2025 |
| Intelligence score | 27 |
| Speed | — |
| Latency (TTFT) | — |
| Input price | $0.20 / 1M tokens |
| Output price | $0.50 / 1M tokens |
| Context window | 4 tokens |
| Parameters | — |
| Reasoning | Yes |
| Input modalities | text, image |
| Output modalities | — |
| Open weights | No |
| License | — |
| API availability | — |
| Source | Model Intelligence legacy profile: grok-4-fast-reasoning |
Pricing
Token prices
Price per 1M tokens
Grok 4 Fast, as listed in the catalog record
- Input$0.20
- Output$0.50
| Token type | Price per 1M |
|---|---|
| Input | $0.20 |
| Output | $0.50 |
Model Intelligence legacy profile: grok-4-fast-reasoning
FAQ · 16
Frequently asked questions
Grok 4 Fast (Reasoning) was released on September 19, 2025.
Grok 4 Fast (Reasoning) was created by xAI.
Grok 4 Fast (Reasoning) scores 27 (estimated) on the Artificial Analysis Intelligence Index, placing it well above average among other reasoning models in a similar price tier (median: 15).
Grok 4 Fast (Reasoning) costs $0.20 per 1M input tokens (better than average, median: $0.25) and $0.50 per 1M output tokens (better than average, median: $0.87), based on the median across providers serving the model.
Grok 4 Fast (Reasoning) costs $0.20 per 1M input tokens and $0.50 per 1M output tokens (based on the median across providers serving the model). For a blended rate (7:2:1 cache hit/input/output ratio), this is $0.23 per 1M tokens. Pricing may vary by provider.
Yes, Grok 4 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 Fast (Reasoning) supports text and image input.
Grok 4 Fast (Reasoning) supports text output.
Yes, Grok 4 Fast (Reasoning) supports image input and can analyze, describe, and answer questions about images.
Yes, Grok 4 Fast (Reasoning) is multimodal. It can process text and image input and generate text output.
Grok 4 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 Fast (Reasoning) is proprietary. The model weights are not publicly available.
Grok 4 Fast (Reasoning) is a proprietary model and xAI has not disclosed the model size or parameter count.
Grok 4 Fast (Reasoning) achieves a score of 27 on the Artificial Analysis Intelligence Index. This composite benchmark evaluates models across reasoning, knowledge, mathematics, and coding.
Yes, Grok 4 Fast (Reasoning) is available via API through 1 provider.
Grok 4 Fast (Reasoning) is available through 1 API provider.