Grok 4 Fast
Sep 2025
Grok 4 FastCompare inon
Benchmarks of Grok 4 Fast43
BenchmarkByScoreRank
Overall1
Knowledge5
Reasoning4
Science2
Coding4
Agents1
Multimodal1
Writing17
Health & law3
Documents1
Legacy · saturated or no longer reported4
No benchmark matches
—per task?
not available via APIprice
—output speed?
2Mcontext
Rankingin thinking mode?
Retired models are left out of the current rankings.
Alternatives?
ModelScoreCostPer taskWhat changes
BetterGPT-6 Lunalow+20%—$0.005Context: 2M → 1.05M+4
OpenMiMo v2.6 Prothinking×2.6—$0.13Context: 2M → 1M+4BetterGPT-5.6 Lunalow+17%—$0.01Context: 2M → 1.05M
BetterClaude Haiku 5.5low+64%—$0.024Context: 2M → 1M+6
BetterLing 3.0 FlashthinkingOpen+12%—$0.028Context: 2M → 262K+1ModelScoreCostPer taskWhat changes
Nothing here yet.
ModelScoreCostPer taskWhat changes
GPT-6 Lunalow+20%—$0.005Context: 2M → 1.05M+4GPT-5.6 Lunalow+17%—$0.01Context: 2M → 1.05MClaude Haiku 5.5low+64%—$0.024Context: 2M → 1M+6Ling 3.0 FlashthinkingOpen+12%—$0.028Context: 2M → 262K+1MiMo v2.5thinkingOpen+22%—$0.042Context: 2M → 1MModelScoreCostPer taskWhat changes
MiMo v2.6 ProthinkingOpen×2.6—$0.13Context: 2M → 1M+4
DeepSeek V4.1 Flash 1017maxOpen×2.5—$0.26Context: 2M → 1M+5
GLM 5.3maxOpen×2.5—$2.01Context: 2M → 1M+5
Step 5 PreviewthinkingOpen×2.4—$1.03Context: 2M → 1M+3
Kimi K3maxOpen×2.4—$2.00Context: 2M → 1M+4ModelScoreCostPer taskWhat changes
Grok 4.6medium×2.4—$1.14Context: 2M → 500KGrok 4.7low×2.4—$1.03Context: 2M → 500K+5Grok 4.5high×2.2—$0.76Context: 2M → 500KGrok Build 0.1thinking+51%—$1 / $2Context: 2M → 256KGrok 4.3medium+38%—$1.25 / $2.50Context: 2M → 1MGrok 4.20 Multi-Agentn/a—$1.25 / $2.50Grok 4.20 Non-Reasoningn/a—$1.25 / $2.50Context: not verifiedGrok 4.20 Reasoningn/a—$1.25 / $2.50Context: not verifiedAll xAI models →History
2 versionsBenchmarks
all categoriesChat & Knowledge
Arena Text · overall1,405
Arena Text · Chinese1,436.3
Arena Text · English1,406.5
Arena Text · French1,431.7
Arena Text · German1,382.8
Arena Text · Japanese1,352.5
Arena Text · Korean1,357.1
Arena Text · non-English1,388.5
Arena Text · Polish1,379.2
Arena Text · Russian1,388.8
Arena Text · Spanish1,404.1
AA Omniscience Index-29.9
Vals LegalBench80.6
Vals MedCode37.4
Vals MedScribe81.6
GPQA Diamond84.7
Coding
WebDev Arena1,159
Agents & Tool Use
τ²-bench · AA65.8
Writing & Language
Vision & Documents
FAQ
How much does Grok 4 Fast cost?›
There is no per-unit API price: not available via API.
Is Grok 4 Fast free to use?›
There is no free API.
What is the context window of Grok 4 Fast?›
2M tokens.
When was Grok 4 Fast released? Is there a newer version?›
Released 2025-09-19. It has been superseded by Grok 4.3.
Is Grok 4 Fast open source?›
No, Grok 4 Fast is a closed model available through an API. The closest open-weights option here is MiMo v2.6 Pro.
Can Grok 4 Fast read images?›
It accepts text and images, PDF files as input.
What is Grok 4 Fast?›
Grok 4 Fast is a closed language model from xAI, released Sep 2025.
What are the best alternatives to Grok 4 Fast?›
GPT-6 Luna (better), MiMo v2.6 Pro (open weights).