Compare / head-to-head
Grok 4 Fast ReasoningvsKimi K3
Kimi K3 leads 2 of 2 shared benchmarks. Grok 4 Fast Reasoning is 25.7x cheaper per token. Grok 4 Fast Reasoning has the larger context window (2M tokens).
Benchmarks from cited public sources; pricing from official pages; status from official provider feeds.
Shared benchmarks
0 – 2
Kimi K3 leads
Cheaper per token
Grok 4 Fast Reasoning
25.7x cheaper, input + output
Larger context
Grok 4 Fast Reasoning
2M tokens
Provider uptime (30d)
— · 100%
xAI · Moonshot AI
Grok 4 Fast Reasoning
xAI · released 2025-09-19
text
Quality
Benchmark matrix
2 shared · 10 only Grok 4 Fast Reasoning · 55 only Kimi K3| Benchmark | Grok 4 Fast Reasoning | Kimi K3 | Δ | Edge |
|---|---|---|---|---|
| Reported by both · 2 | ||||
| GPQA Diamond | 85.7% ↗ | 93.5% ↗ | -7.8 pt | Kimi K3 |
| Humanity's Last Exam (no tools) | 20% ↗ | 43.5% ↗ | -23.5 pt | Kimi K3 |
| Only Grok 4 Fast Reasoning reports · 10 | ||||
| AIME 2025 | 92% ↗ | not reported | — | — |
| BrowseComp | 44.9% ↗ | not reported | — | — |
| BrowseComp (zh) | 51.2% ↗ | not reported | — | — |
| HMMT 2025 (no tools) | 93.3% ↗ | not reported | — | — |
| LiveCodeBench (Jan-May) | 80% ↗ | not reported | — | — |
| Reka Research Eval | 66% ↗ | not reported | — | — |
| Search Arena Elo | 1163 ↗ | not reported | — | — |
| SimpleQA | 95% ↗ | not reported | — | — |
| X Bench Deepsearch (zh) | 74% ↗ | not reported | — | — |
| X Browse | 58% ↗ | not reported | — | — |
| Only Kimi K3 reports · 55 | ||||
| AIME 2026 | not reported | 96.7% ↗matharena ⚠ | — | — |
| AA-Briefcase | not reported | 1548 ↗ | — | — |
| AA-LCR | not reported | 74.7% ↗ | — | — |
| Agents' Last Exam | not reported | 28.3% ↗ | — | — |
| APEX-Agents | not reported | 41% ↗ | — | — |
| AutomationBench | not reported | 30.8% ↗ | — | — |
| BabyVision (with Python) | not reported | 85.7% ↗ | — | — |
| BrowseComp (1M context, no compaction) | not reported | 90.4% ↗ | — | — |
| BrowseComp (context compaction) | not reported | 91.2% ↗ | — | — |
| CharXiv Reasoning (no tools) | not reported | 84.8% ↗ | — | — |
| CharXiv Reasoning (with Python) | not reported | 91.3% ↗ | — | — |
| CorpFin v2 | not reported | 71.6% ↗ | — | — |
| CritPt | not reported | 23.4% ↗ | — | — |
| DeepSearchQA (F1) | not reported | 95% ↗ | — | — |
| DeepSWE v1.1 | not reported | 67.3% ↗ | — | — |
| DeepSWE v1.1 (Kimi Code) | not reported | 67.5% ↗ | — | — |
| Finance Agent v2 | not reported | 54.4% ↗ | — | — |
| FrontierMath Tier 4 v2 (Epoch AI run) | not reported | 39% ↗epoch | — | — |
| FrontierMath Tiers 1-3 v2 (Epoch AI run) | not reported | 72.2% ↗epoch | — | — |
| FrontierSWE | not reported | 81.2% ↗ | — | — |
| GDPval-AA v2 | not reported | 1686 ↗ | — | — |
| Harvey Lab-AA | not reported | 94.6% ↗ | — | — |
| Humanity's Last Exam (with tools) | not reported | 56% ↗ | — | — |
| JobBench | not reported | 54.3% ↗ | — | — |
| Kimi Code Bench 2.0 | not reported | 72.9% ↗ | — | — |
| Legal Research Bench | not reported | 44.2% ↗ | — | — |
| MathVision (no tools) | not reported | 94.3% ↗ | — | — |
| MathVision (with Python) | not reported | 97.8% ↗ | — | — |
| MCP-Atlas | not reported | 84.2% ↗ | — | — |
| MCPMark-Verified | not reported | 94.5% ↗ | — | — |
| MLS-Bench-Lite | not reported | 48.3% ↗ | — | — |
| MMMU-Pro (no tools) | not reported | 81.6% ↗ | — | — |
| MMMU-Pro (with Python) | not reported | 83.4% ↗ | — | — |
| MMVU | not reported | 82.1% ↗ | — | — |
| OfficeQA Pro | not reported | 63.3% ↗ | — | — |
| OmniDocBench | not reported | 91.1% ↗ | — | — |
| OSWorld 2.0 | not reported | 58.3% ↗ | — | — |
| OSWorld-Verified | not reported | 84.8% ↗ | — | — |
| OTIS Mock AIME 2024-2025 (Epoch AI run) | not reported | 97.2% ↗epoch | — | — |
| PerceptionBench | not reported | 58.5% ↗ | — | — |
| PostTrainBench | not reported | 36.6% ↗ | — | — |
| ProgramBench | not reported | 77.8% ↗ | — | — |
| ResearchRubrics | not reported | 76.2% ↗ | — | — |
| SaaS-Bench | not reported | 60.1% ↗ | — | — |
| SciCode | not reported | 58.7% ↗ | — | — |
| SimpleQA Verified | not reported | 50.6% ↗epoch | — | — |
| SpreadsheetBench 2 | not reported | 34.8% ↗ | — | — |
| SWE-Marathon | not reported | 42% ↗ | — | — |
| tau3-Banking | not reported | 33.4% ↗ | — | — |
| Terminal-Bench 2.1 | not reported | 88.3% ↗ | — | — |
| Toolathlon-Verified | not reported | 76.5% ↗ | — | — |
| Video-MME (with subtitles) | not reported | 90% ↗ | — | — |
| WorldVQA ForceAnswer | not reported | 51% ↗ | — | — |
| ZeroBench pass@5 (no tools) | not reported | 23% ↗ | — | — |
| ZeroBench pass@5 (with Python) | not reported | 41% ↗ | — | — |
Scores tagged "epoch" or "matharena" are independent runs, used only where the lab has not published its own; ⚠ marks rows MathArena flags as released after the competition. Higher is better on every row. Δ is Grok 4 Fast Reasoning minus Kimi K3 in the benchmark's own unit. "Not reported" means the lab has not published that figure; it is not a zero. ↗ opens the source.
Specs & pricing
Side by side
Official pricing pages and model cards| Spec | Grok 4 Fast Reasoning | Kimi K3 | Edge |
|---|---|---|---|
| Context window | 2M tokens | 1M tokens | Grok 4 Fast Reasoning |
| Max output | — | 1.0M tokens | — |
| Input price / 1M | $0.2 ↗ | $3 ↗ | Grok 4 Fast Reasoning |
| Output price / 1M | $0.5 ↗ | $15 ↗ | Grok 4 Fast Reasoning |
| Cached input / 1M | $0.05 ↗ | $0.3 ↗ | Grok 4 Fast Reasoning |
| Input + output / 1M Lower is cheaper. List prices; batch, tool and regional fees excluded. | $0.7 | $18 | Grok 4 Fast Reasoning |
| Modalities | text | text · vision | Kimi K3 |
| Released | 2025-09-19 | 2026-07-16 | — |
| Cited benchmark scores | 12 | 59 | — |
Reliability
Provider status
Last 60 days · refreshed daily on this page · live on /statusMore matchups
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Which one wins on your data?
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