Model comparison

Grok 4.3 vs Kimi K2 (Jul 2025)

Grok 4.3 is the stronger model overall, scoring 43.8 to 41.2 on the Noometry Index. Kimi K2 (Jul 2025) costs 1.6× less per token, which makes it the better buy when Grok 4.3's lead doesn't matter for your workload.

Last verified . 21 shared benchmarks.

Grok 4.3 xAI

43.8

Rank #86 Confirmed

Kimi K2 (Jul 2025) Moonshot AI

41.2

Rank #140 Confirmed

Summary

  • They share 21 benchmarks with published results for both. Grok 4.3 scores higher in 6 categories and Kimi K2 (Jul 2025) in 3 categories; 6 gaps are clear of the uncertainty.
  • The widest gap is in knowledge, where Grok 4.3 leads 52.5 to 37.3.
  • The biggest single-benchmark swing is WeirdML: 49.9% for Grok 4.3 and 42.8% for Kimi K2 (Jul 2025).
  • Kimi K2 (Jul 2025) is cheaper at $0.57 / $2.30 per million input/output tokens, against $1.25 / $2.50 for Grok 4.3.
  • Grok 4.3 accepts more context: 1M tokens versus 262K.
  • Kimi K2 (Jul 2025) has downloadable open weights; the other is API-only.

Side by side

Grok 4.3 and Kimi K2 (Jul 2025) specifications
Grok 4.3Kimi K2 (Jul 2025)
ProviderxAIMoonshot AI
Noometry Index43.841.2
Released2026-04-172025-07-12
WeightsProprietaryOpen
Context window1M262K
Max output30K262K
Input $ / M tokens$1.25$0.57
Output $ / M tokens$2.50$2.30
Results tracked4042

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Category by category

Coding Too close to call

Grok 4.3: 41.6 (#121), Kimi K2 (Jul 2025): 42.4 (#102)

Coding benchmarks
BenchmarkGrok 4.3Kimi K2 (Jul 2025)
WeirdML49.9%42.8%
LMArena Coding14151399
ALE-Bench944.17597.5
SWE-bench Verified (bash only)—63.4%
Aider Polyglot—59.1%
LMArena WebDev1357—
SciCode47.3%—
GSO—4.9%

Agentic & Tool Use Kimi K2 (Jul 2025) leads

Grok 4.3: 27.7 (#99), Kimi K2 (Jul 2025): 32.4 (#64)

Agentic & Tool Use benchmarks
BenchmarkGrok 4.3Kimi K2 (Jul 2025)
Terminal-Bench—35.7%
Berkeley Function Calling Leaderboard—59.1%
GDP.pdf8%—
LMArena Search1165—
METR Time Horizons—59.2%
Vending-Bench 235.26—

Reasoning Grok 4.3 leads

Grok 4.3: 35.9 (#68), Kimi K2 (Jul 2025): 23.3 (#179)

Reasoning benchmarks
BenchmarkGrok 4.3Kimi K2 (Jul 2025)
LMArena Hard Prompts13961384
Epoch Capabilities Index149.16146.01
ForecastBench60.360.2
SimpleBench—26.3%
Kagi LLM Benchmark—64.4%
NYT Connections (extended)55.2%—
CritPt8%—
Chess Puzzles25%—
DTBench90.7%—
LMCA38.3%—

Math Grok 4.3 leads

Grok 4.3: 46.0 (#74), Kimi K2 (Jul 2025): 42.7 (#83)

Math benchmarks
BenchmarkGrok 4.3Kimi K2 (Jul 2025)
LMArena Math13881397
FrontierMath (Tiers 1-3)42.8%—
FrontierMath Tier 414.6%—
OTIS Mock AIME 2024-202593.3%—
ProofBench11%—
Omni-MATH—65.4%
FrontierMath (Feb 2025 set)—21.4%
FrontierMath Tier 4 (v1)—0%

Knowledge Grok 4.3 leads

Grok 4.3: 52.5 (#62), Kimi K2 (Jul 2025): 37.3 (#157)

Knowledge benchmarks
BenchmarkGrok 4.3Kimi K2 (Jul 2025)
LMArena Expert13851365
GPQA Diamond88.8%—
SimpleQA Verified33.2%—
MMLU-Pro—81.9%
Confabulations—20.4%
Vectara Hallucination Rate—17.9%
GPQA (HELM)—65.3%

Multimodal Not comparable

Grok 4.3: 31.6 (#104), Kimi K2 (Jul 2025): —

Multimodal benchmarks
BenchmarkGrok 4.3Kimi K2 (Jul 2025)
LMArena Vision1229—
Blueprint-Bench 20%—

Multilingual Too close to call

Grok 4.3: 50.5 (#120), Kimi K2 (Jul 2025): 49.6 (#130)

Multilingual benchmarks
BenchmarkGrok 4.3Kimi K2 (Jul 2025)
LMArena Non-English13851372
LMArena Chinese14221415
LMArena French14121379
LMArena German13951387
LMArena Japanese13791349
LMArena Korean13561325
LMArena Russian13991385
LMArena Spanish13981386

Instruction Following Too close to call

Grok 4.3: 72.1 (#140), Kimi K2 (Jul 2025): 71.1 (#156)

Instruction Following benchmarks
BenchmarkGrok 4.3Kimi K2 (Jul 2025)
LMArena Instruction Following13661348
IFEval—85%

Long Context Grok 4.3 leads

Grok 4.3: 42.5 (#123), Kimi K2 (Jul 2025): 41.2 (#145)

Long Context benchmarks
BenchmarkGrok 4.3Kimi K2 (Jul 2025)
LMArena Longer Query13931353
Fiction.LiveBench—66.7%
CL-bench—17.6%

Writing & Preference Kimi K2 (Jul 2025) leads

Grok 4.3: 58.5 (#118), Kimi K2 (Jul 2025): 62.3 (#78)

Writing & Preference benchmarks
BenchmarkGrok 4.3Kimi K2 (Jul 2025)
LMArena Text13971380
LMArena Creative Writing13801350
LMArena Multi-Turn14061371
Short-Story Creative Writing—85.6%
EQ-Bench Creative Writing—1666
WildBench—86.2%
EQ-Bench 41075—

Frequently asked questions

Is Grok 4.3 better than Kimi K2 (Jul 2025)?

Grok 4.3 is the stronger model overall, scoring 43.8 to 41.2 on the Noometry Index. Kimi K2 (Jul 2025) costs 1.6× less per token, which makes it the better buy when Grok 4.3's lead doesn't matter for your workload.

Which is cheaper, Grok 4.3 or Kimi K2 (Jul 2025)?

Kimi K2 (Jul 2025) is cheaper. It lists at $0.57 per million input tokens and $2.30 per million output tokens; Grok 4.3 lists at $1.25 and $2.50.

Is Grok 4.3 or Kimi K2 (Jul 2025) better for coding?

They score almost the same on coding (41.6 vs 42.4); test both on your own repository before choosing.

Which has the bigger context window?

Grok 4.3 does, with 1M tokens against 262K.

How many benchmarks do Grok 4.3 and Kimi K2 (Jul 2025) share?

21 benchmarks have published results for both models. Grok 4.3 has 40 scored results on Noometry and Kimi K2 (Jul 2025) has 42.

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