xAI model product
Grok 4 Fast
Grok 4 Fast is a high-speed variant of Grok-4 from xAI, optimized for faster inference with improved throughput and lower latency.
Updated Oct 23, 2026. Default version: Grok 4 Fast
LLMBoard Score51.4Grok 4 Fast
Coverage80%7 benchmark families
Context window2MTokens
Official input priceN/AOfficial price unavailable
Grok 4 Fast Capability Profile
This profile uses the model's current scored version. Arena ratings and prices are shown separately.
Grok 4 Fast Benchmark Results
Benchmark scores for Grok 4 Fast.
Sort by
Benchmark | Score | Rank | Participants | Percentile | Evidence | Evaluated |
|---|
| BenchmarkSimpleQA | Score95.00% | Rank02 | Participants47 | Percentile97.83% | EvidenceC | Evaluated |
| BenchmarkLiveCodeBench | Score80.00% | Rank12 | Participants76 | Percentile85.33% | EvidenceC | Evaluated |
| BenchmarkHMMT 2025 | Score93.30% | Rank13 | Participants33 | Percentile62.50% | EvidenceC | Evaluated |
| BenchmarkLM Arena Search | Score1,170.10 rating | Rank23 | Participants33 | Percentile31.25% | EvidenceA | Evaluated |
| BenchmarkLM Arena Search Factuality | Score1,146.00 rating | Rank28 | Participants33 | Percentile15.63% | EvidenceA | Evaluated |
| BenchmarkLM Arena Search Style Control | Score1,161.08 rating | Rank28 | Participants33 | Percentile15.63% | EvidenceA | Evaluated |
| BenchmarkAIME 2025 | Score92.00% | Rank41 | Participants122 | Percentile66.94% | EvidenceC | Evaluated |
| BenchmarkBrowseComp | Score44.90% | Rank59 | Participants70 | Percentile15.94% | EvidenceC | Evaluated |
| BenchmarkAA AIME 2025 | Score41.33% | Rank61 | Participants96 | Percentile36.84% | EvidenceB | EvaluatedN/A |
| BenchmarkGPQA | Score85.70% | Rank65 | Participants256 | Percentile74.90% | EvidenceC | Evaluated |
| BenchmarkHumanity's Last Exam | Score20.00% | Rank73 | Participants109 | Percentile33.33% | EvidenceC | Evaluated |
| BenchmarkAA IFBench | Score37.69% | Rank127 | Participants168 | Percentile24.55% | EvidenceB | EvaluatedN/A |
| BenchmarkAA CritPt | Score0.00% | Rank140 | Participants200 | Percentile30.15% | EvidenceB | EvaluatedN/A |
| BenchmarkAA Omniscience Accuracy | Score17.70% | Rank143 | Participants201 | Percentile29.00% | EvidenceB | EvaluatedN/A |
| BenchmarkAA LCR v1.1 | Score24.00% | Rank157 | Participants193 | Percentile18.75% | EvidenceB | EvaluatedN/A |
| BenchmarkAA GPQA Diamond | Score60.61% | Rank158 | Participants199 | Percentile20.71% | EvidenceB | EvaluatedN/A |
| BenchmarkAA HLE Text No Tools | Score4.54% | Rank167 | Participants200 | Percentile16.58% | EvidenceB | EvaluatedN/A |
Grok 4 Fast Arena Results
Preference and agent-evaluation results for the default version.
Sort by
Arena | Category | Rank | Rating / score | Votes | Observations | Result date |
|---|
| Arenasearch | Categoryoverall | Rank23 | Rating / score1,170.10 | Votes43,083 | ObservationsN/A | Result date |
| Arenasearch factuality | Categoryoverall | Rank28 | Rating / score1,146.00 | Votes30,673 | ObservationsN/A | Result date |
| Arenasearch style control | Categoryoverall | Rank28 | Rating / score1,161.08 | Votes43,083 | ObservationsN/A | Result date |
Grok 4 Fast Pricing
Official vendor API pricing appears first, followed by individual provider offers.
- Official API
- N/A
- Official provider
- N/A
- Lowest third-party
- N/A
- Tracked offerings
- 0
No provider prices
The default version has no current input or output token prices.
Official prices use only the vendor's configured official Provider and positive standard USD PAYG rates. Third-party offers remain explicitly labeled.
Grok 4 Fast Runtime Performance
Provider-specific output speed and catalog latency for Grok 4 Fast. Runtime does not affect the capability score.
Sort by
Provider | Output Speed | Catalog Latency | Max Input | Max Output | Updated |
|---|
| ProviderxAI | Output Speed90.00 tok/s | Catalog LatencyN/A | Max Input2M | Max Output30K | Updated |
Output Speed is generated output tokens received per second. Catalog latency is reported separately from observed provider TTFT.
Grok 4 Fast Specifications
Technical details for the model's default version.
- Version
- Grok 4 Fast
- Released
- Aug 28, 2025
- Knowledge cutoff
- Unknown
- Parameters
- N/A
- Context window
- 2M
- Max output
- 30K
- Inputs
- image, text
- Outputs
- text
- Open weights
- No
- License
- Proprietary
Grok 4 Fast Versions
Available versions of this model. The score column identifies the version used in the overall ranking.
Sort by
Version | Released | LLMBoard | Parameters | Context | Max output | Open weights | License |
|---|
| VersionGrok 4 Fast | Released | LLMBoard51.44 | ParametersN/A | Context2M | Max output30K | Open weightsNo | LicenseProprietary |
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What is Grok 4 Fast?
Key information about Grok 4 Fast and its available data.
Grok 4 Fast is a large language model from xAI and a high-speed variant of Grok-4. It is optimized for faster inference while maintaining strong reasoning capabilities.
Data as of 2026-10-22.
FAQ
Common questions about Grok 4 Fast.
When was Grok 4 Fast released?
Grok 4 Fast's default version was released on Aug 28, 2025.
How much does Grok 4 Fast cost?
No official standard PAYG price is currently available for Grok 4 Fast.
Who created Grok 4 Fast?
Grok 4 Fast was created by xAI.
What is the context window for Grok 4 Fast?
The default version has a 2M token context window.
Is Grok 4 Fast open weight?
No. The default version is not marked as having publicly available weights.
How many API providers offer Grok 4 Fast?
No provider offering is currently linked to the default version.