Noometry

Model comparison

Grok 4 Fast vs Kimi K2.6

Kimi K2.6 is the stronger model overall, scoring 47.7 to 39.4 on the Noometry Index.

Last verified . 22 shared benchmarks.

Grok 4 Fast xAI

39.4

Rank #167 Confirmed

Kimi K2.6 Moonshot AI

47.7

Rank #60 Confirmed

Summary

  • They share 22 benchmarks with published results for both. Grok 4 Fast scores higher in 2 categories and Kimi K2.6 in 7 categories; 9 gaps are clear of the uncertainty.
  • The widest gap is in knowledge, where Kimi K2.6 leads 54.0 to 32.0.
  • The biggest single-benchmark swing is WeirdML: 42.9% for Grok 4 Fast and 55.9% for Kimi K2.6.
  • Kimi K2.6 has downloadable open weights; the other is API-only.

Side by side

Grok 4 FastKimi K2.6
ProviderxAIMoonshot AI
Noometry Index39.447.7
Released2025-09-192026-04-20
WeightsProprietaryOpen
Context window—262K
Max output—262K
Input $ / M tokens—$0.95
Output $ / M tokens—$4
Results tracked3051

Sponsored placements are available on pages like this one. Advertise on Noometry

Category by category

Coding Kimi K2.6 leads

Grok 4 Fast: 32.5 (#271), Kimi K2.6: 50.7 (#43)

BenchmarkGrok 4 FastKimi K2.6
LMArena WebDev11591509
WeirdML42.9%55.9%
LMArena Coding14291488
SWE-bench Verified—76.7%
SciCode—53.5%
ALE-Bench—1,093

Agentic & Tool Use Grok 4 Fast leads

Grok 4 Fast: 29.5 (#86), Kimi K2.6: 21.9 (#137)

BenchmarkGrok 4 FastKimi K2.6
OSWorld 2.0—4.6%
τ²-bench Banking15.7%—
Cybench30%—
ExploitBench—18.4%
GBAEval—0.9%
GDP.pdf—12%
LMArena Search1171—
Vending-Bench 2—6,205

Reasoning Kimi K2.6 leads

Grok 4 Fast: 22.2 (#201), Kimi K2.6: 40.5 (#55)

BenchmarkGrok 4 FastKimi K2.6
LMArena Hard Prompts14121470
DTBench82.7%90.9%
Epoch Capabilities Index144.2151.05
ARC-AGI-25.3%—
Kagi LLM Benchmark66.1%—
NYT Connections (extended)—87.2%
ARC-AGI-148.5%—
CritPt—8%
Chess Puzzles—26%
EBR-Bench—2.4%
Mystery Game Puzzles—18%
LMCA—37.3%
ForecastBench60.5—

Math Kimi K2.6 leads

Grok 4 Fast: 38.9 (#123), Kimi K2.6: 57.0 (#41)

BenchmarkGrok 4 FastKimi K2.6
LMArena Math14191475
FrontierMath (Tiers 1-3)—57.2%
FrontierMath Tier 4—25.6%
MathArena Final-Answer Competitions—72.9%
OTIS Mock AIME 2024-2025—96.1%
ProofBench—16%
FrontierMath (Feb 2025 set)—39%
FrontierMath Tier 4 (v1)—14.6%

Knowledge Kimi K2.6 leads

Grok 4 Fast: 32.0 (#214), Kimi K2.6: 54.0 (#54)

BenchmarkGrok 4 FastKimi K2.6
Vectara Hallucination Rate19.7%10.8%
LMArena Expert14111491
GPQA Diamond—90.8%
SimpleQA Verified—34.9%

Multimodal Not comparable

Grok 4 Fast: —, Kimi K2.6: 31.6 (#103)

BenchmarkGrok 4 FastKimi K2.6
LMArena Vision—1283
Blueprint-Bench 2—3.9%
Furniture Assembly—21.7%
LMArena Document—1451

Multilingual Kimi K2.6 leads

Grok 4 Fast: 51.3 (#111), Kimi K2.6: 54.9 (#37)

BenchmarkGrok 4 FastKimi K2.6
LMArena Non-English13961446
LMArena Chinese14571521
LMArena French14311471
LMArena German13831450
LMArena Japanese13521443
LMArena Korean13571427
LMArena Russian13891446
LMArena Spanish14151464

Instruction Following Kimi K2.6 leads

Grok 4 Fast: 73.2 (#121), Kimi K2.6: 76.3 (#43)

BenchmarkGrok 4 FastKimi K2.6
LMArena Instruction Following13871451

Long Context Grok 4 Fast leads

Grok 4 Fast: 63.2 (#3), Kimi K2.6: 44.9 (#52)

BenchmarkGrok 4 FastKimi K2.6
LMArena Longer Query14151468
Fiction.LiveBench94.4%—

Writing & Preference Kimi K2.6 leads

Grok 4 Fast: 60.0 (#102), Kimi K2.6: 68.5 (#26)

BenchmarkGrok 4 FastKimi K2.6
LMArena Text14071455
LMArena Creative Writing13871434
LMArena Multi-Turn14141453
EQ-Bench Creative Writing—1725
EQ-Bench 4—1202

Frequently asked questions

Is Grok 4 Fast better than Kimi K2.6?

Kimi K2.6 is the stronger model overall, scoring 47.7 to 39.4 on the Noometry Index.

Is Grok 4 Fast or Kimi K2.6 better for coding?

Kimi K2.6 scores higher on coding benchmarks: 50.7 versus 32.5 in the Noometry coding category.

How many benchmarks do Grok 4 Fast and Kimi K2.6 share?

22 benchmarks have published results for both models. Grok 4 Fast has 30 scored results on Noometry and Kimi K2.6 has 51.

Related comparisons

Go deeper