Model comparison

Grok 4.1 Fast vs Kimi K2.6

Kimi K2.6 is the stronger model overall, scoring 47.5 to 40.9 on the Noometry Index. Grok 4.1 Fast costs 6.2× less per token, which makes it the better buy when Kimi K2.6's lead doesn't matter for your workload.

Last verified . 27 shared benchmarks.

Grok 4.1 Fast xAI

40.9

Rank #131 Confirmed

Kimi K2.6 Moonshot AI

47.5

Rank #52 Confirmed

Summary

  • They share 27 benchmarks with published results for both. Grok 4.1 Fast scores higher in 3 categories and Kimi K2.6 in 7 categories; 10 gaps are clear of the uncertainty.
  • The widest gap is in math, where Kimi K2.6 leads 56.8 to 30.9.
  • The biggest single-benchmark swing is ProofBench: 4% for Grok 4.1 Fast and 16% for Kimi K2.6.
  • Grok 4.1 Fast is cheaper at $0.20 / $0.50 per million input/output tokens, against $0.95 / $4 for Kimi K2.6.
  • Kimi K2.6 accepts more context: 262K tokens versus 128K.
  • Kimi K2.6 has downloadable open weights; the other is API-only.

Side by side

Grok 4.1 Fast and Kimi K2.6 specifications
Grok 4.1 FastKimi K2.6
ProviderxAIMoonshot AI
Noometry Index40.947.5
Released2025-06-272026-04-20
WeightsProprietaryOpen
Context window128K262K
Max output30K262K
Input $ / M tokens$0.20$0.95
Output $ / M tokens$0.50$4
Results tracked3251

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Category by category

Coding Kimi K2.6 leads

Grok 4.1 Fast: 33.8 (#236), Kimi K2.6: 50.5 (#41)

Coding benchmarks
BenchmarkGrok 4.1 FastKimi K2.6
LMArena WebDev12411509
LMArena Coding14111488
ALE-Bench394.931,093
SWE-bench Verified—76.7%
SciCode—53.5%
WeirdML—55.9%

Agentic & Tool Use Grok 4.1 Fast leads

Grok 4.1 Fast: 36.1 (#35), Kimi K2.6: 21.8 (#128)

Agentic & Tool Use benchmarks
BenchmarkGrok 4.1 FastKimi K2.6
Vending-Bench 21,1076,205
Berkeley Function Calling Leaderboard69.6%—
OSWorld 2.0—4.6%
τ²-bench Banking13.1%—
ExploitBench—18.4%
GBAEval—0.9%
GDP.pdf—12%
LMArena Search1171—

Reasoning Grok 4.1 Fast leads

Grok 4.1 Fast: 42.3 (#45), Kimi K2.6: 39.6 (#51)

Reasoning benchmarks
BenchmarkGrok 4.1 FastKimi K2.6
NYT Connections (extended)87.4%87.2%
LMArena Hard Prompts14071470
DTBench87.7%90.9%
SimpleBench56%—
CritPt—8%
Chess Puzzles—26%
EBR-Bench—2.4%
Mystery Game Puzzles—18%
LMCA—37.3%
Epoch Capabilities Index—151.03
ForecastBench61—

Math Kimi K2.6 leads

Grok 4.1 Fast: 30.9 (#201), Kimi K2.6: 56.8 (#34)

Knowledge Kimi K2.6 leads

Grok 4.1 Fast: 32.6 (#203), Kimi K2.6: 53.9 (#48)

Knowledge benchmarks
BenchmarkGrok 4.1 FastKimi K2.6
Vectara Hallucination Rate17.8%10.8%
LMArena Expert13981491
GPQA Diamond—90.8%
SimpleQA Verified—34.9%

Multimodal Grok 4.1 Fast leads

Grok 4.1 Fast: 36.3 (#71), Kimi K2.6: 31.8 (#95)

Multimodal benchmarks
BenchmarkGrok 4.1 FastKimi K2.6
LMArena Vision12011282
Blueprint-Bench 2—3.9%
Furniture Assembly—21.7%
LMArena Document—1451

Multilingual Kimi K2.6 leads

Grok 4.1 Fast: 51.1 (#110), Kimi K2.6: 55.1 (#35)

Multilingual benchmarks
BenchmarkGrok 4.1 FastKimi K2.6
LMArena Non-English13911446
LMArena Chinese14411521
LMArena French14161471
LMArena German14041449
LMArena Japanese13471442
LMArena Korean13611428
LMArena Russian13871446
LMArena Spanish14111463

Instruction Following Kimi K2.6 leads

Grok 4.1 Fast: 72.8 (#127), Kimi K2.6: 76.5 (#40)

Instruction Following benchmarks
BenchmarkGrok 4.1 FastKimi K2.6
LMArena Instruction Following13761451

Long Context Kimi K2.6 leads

Grok 4.1 Fast: 42.4 (#121), Kimi K2.6: 44.9 (#50)

Long Context benchmarks
BenchmarkGrok 4.1 FastKimi K2.6
LMArena Longer Query13901468

Writing & Preference Kimi K2.6 leads

Grok 4.1 Fast: 57.4 (#126), Kimi K2.6: 68.7 (#25)

Writing & Preference benchmarks
BenchmarkGrok 4.1 FastKimi K2.6
LMArena Text14081455
LMArena Creative Writing13941434
EQ-Bench Creative Writing13271725
LMArena Multi-Turn13891453
EQ-Bench 4—1202

Frequently asked questions

Is Grok 4.1 Fast better than Kimi K2.6?

Kimi K2.6 is the stronger model overall, scoring 47.5 to 40.9 on the Noometry Index. Grok 4.1 Fast costs 6.2× less per token, which makes it the better buy when Kimi K2.6's lead doesn't matter for your workload.

Which is cheaper, Grok 4.1 Fast or Kimi K2.6?

Grok 4.1 Fast is cheaper. It lists at $0.20 per million input tokens and $0.50 per million output tokens; Kimi K2.6 lists at $0.95 and $4.

Is Grok 4.1 Fast or Kimi K2.6 better for coding?

Kimi K2.6 scores higher on coding benchmarks: 50.5 versus 33.8 in the Noometry coding category.

Which has the bigger context window?

Kimi K2.6 does, with 262K tokens against 128K.

How many benchmarks do Grok 4.1 Fast and Kimi K2.6 share?

27 benchmarks have published results for both models. Grok 4.1 Fast has 32 scored results on Noometry and Kimi K2.6 has 51.

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