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Grok 4.20 vs Kimi K3

Updated October 21, 2026. 44 benchmarks have a result for both. Coding is ranked on the Vibe Coding Index; every other board is shown as published.

Replace Grok 4.20 Replace Kimi K3
Grok 4.20xAI
Coding
33.3
Overall
25.7
Output $/M
$2.50
1
Kimi K3Moonshot AI
Coding
62.3
Overall
43.6
Output $/M
$15.00
43
vs boards won of 44 shared

Decision reading

Pick Kimi K3 for coding: it scores 62.3 on the Vibe Coding Index against 33.3 for Grok 4.20.

Pick Grok 4.20 when output tokens cost 6.0x less, or when a solved task costs $0.72 against $0.81.

Model AGrok 4.20xAI33.3/1002 independent benchmarks$0.72 per solved taskModel BKimi K3Moonshot AI62.3/1006 independent benchmarks$0.81 per solved task
Shared results
44
Grok 4.20 only
10
Kimi K3 only
73
Like-for-like categories
7 of 9

Shared results can support a head-to-head reading. Results only one model has describe coverage, not superiority.

Which one for your work

Each card is decided by one number both models carry. Where only one has it, the card says so and makes no call.

At a glance

Coding index
Grok 4.20 33.3 from 2 benchmarks, Kimi K3 62.3 from 6 benchmarks.
Widest category
Coding, 31.3 points apart on average over 6 shared benchmarks.
Widest single gap
Vibe Code Bench (Vals AI): Grok 4.20 4.1% against Kimi K3 85.0%, 80.9 points apart on a 0 to 100 scale.
Output price
Grok 4.20 $2.50 against Kimi K3 $15.00 per million output tokens, 6.0x apart.
Context window
Grok 4.20 takes 2M tokens, Kimi K3 1.05M.

Benchmark by benchmark

First the score: boards each model leads, per category, where both have a result. Then every board, a category to a fold; bars are each result on a 0 to 100 scale, so compare the two in a row, not one row with another.

Boards won, where both have a result
CategoryGrok 4.20BarsKimi K3Ties
Coding06
Intelligence02
Agentic work011
Reasoning15
Knowledge06
Web design07
General06
All shared boards143
CodingLike-for-likeSix of these boards feed the Vibe Coding Index06
Coding benchmarks for Grok 4.20 and Kimi K3
BenchmarkGrok 4.20Kimi K3Leader
LiveBench codingNot measured59.3%Only Kimi K3 measured
LMArena WebDevNot measured1655Only Kimi K3 measured
AA Coding IndexNot measured76.2Only Kimi K3 measured
LiveCodeBench (Vals AI)84.3%87.2%Kimi K3
SWE-bench Verified (Vals AI)72.2%93.4%Kimi K3
Terminal-Bench 4 (Vals AI)Not measured17.2%Only Kimi K3 measured
Vibe Code Bench (Vals AI)4.1%85.0%Kimi K3
Code migration (Vals AI)0.3%16.1%Kimi K3
ProgramBench (Vals AI)Not measured2.0%Only Kimi K3 measured
IOI (Vals AI)Not measured48.9%Only Kimi K3 measured
Terminal-Bench 2.1 (Vals AI)44.2%80.9%Kimi K3
SWE-bench Multimodal (Vals AI)Not measured44.2%Only Kimi K3 measured
Vibe Code Bench 1-100 (Vals AI)Not measured18.2%Only Kimi K3 measured
CyberBench (Vals AI)Not measured75.2%Only Kimi K3 measured
SciCodeNot measured59.5%Only Kimi K3 measured
Terminal-Bench Hard (Artificial Analysis run)37.9%Not measuredOnly Grok 4.20 measured
Terminal-Bench57.3%Not measuredOnly Grok 4.20 measured
FrontierCodeNot measured44.2%Only Kimi K3 measured
FrontierSWENot measured25.9%Only Kimi K3 measured
WeirdML52.3%82.6%Kimi K3
ALE-BenchNot measured1524.5Only Kimi K3 measured
LMArena Text: codingNot measured1508Only Kimi K3 measured
LMArena Text: software and ITNot measured1499Only Kimi K3 measured
LMArena WebDev: ReactNot measured1670Only Kimi K3 measured
LMArena WebDev: HTMLNot measured1644Only Kimi K3 measured
LMArena WebDev: from an imageNot measured1579Only Kimi K3 measured
Neither model has a result on the other 12 boards here
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index02
Intelligence benchmarks for Grok 4.20 and Kimi K3
BenchmarkGrok 4.20Kimi K3Leader
AA Intelligence Index25.743.6Kimi K3
Epoch Capabilities Index152.1157.9Kimi K3
Agentic workLike-for-likePublic boards, shown as published, kept out of the index011
Agentic work benchmarks for Grok 4.20 and Kimi K3
BenchmarkGrok 4.20Kimi K3Leader
AA Agentic IndexNot measured50.0Only Kimi K3 measured
Design Arena: agents building web apps11441295Kimi K3
Design Arena: agents building full-stack apps10541315Kimi K3
Design Arena: agents building mobile apps10901268Kimi K3
Design Arena: agents building Android apps10521256Kimi K3
Design Arena: agents building Godot games10891223Kimi K3
Design Arena: agents building gamesNot measured1252Only Kimi K3 measured
Design Arena: HTML slides11801256Kimi K3
Design Arena: PowerPoint slidesNot measured1273Only Kimi K3 measured
Design Arena: spreadsheetsNot measured1054Only Kimi K3 measured
LiveBench researchNot measured79.0%Only Kimi K3 measured
LiveBench browserNot measured16.0%Only Kimi K3 measured
LiveBench long agenticNot measured42.8%Only Kimi K3 measured
Finance Agent (Vals AI)28.5%53.1%Kimi K3
Tax Agent Bench (Vals AI)7.0%33.4%Kimi K3
Legal Research Bench (Vals AI)13.9%46.1%Kimi K3
Harvey's Legal Agent Benchmark (Vals AI)Not measured12.9%Only Kimi K3 measured
Excel Modeling Benchmark (Vals AI)11.7%66.7%Kimi K3
BioMysteryBench (Vals AI)Not measured72.6%Only Kimi K3 measured
Terminal-Bench-Science (Vals AI)Not measured1.4%Only Kimi K3 measured
Time Horizon Index (Vals AI)Not measured10.5%Only Kimi K3 measured
τ²-Bench Telecom93.0%Not measuredOnly Grok 4.20 measured
APEX-AgentsNot measured47.8%Only Kimi K3 measured
PostTrainBenchNot measured32.0%Only Kimi K3 measured
Vending-Bench 2$4,663$5,165Kimi K3
Neither model has a result on the other 14 boards here
ReasoningLike-for-likePublic boards, shown as published, kept out of the index15
Reasoning benchmarks for Grok 4.20 and Kimi K3
BenchmarkGrok 4.20Kimi K3Leader
GPQA Diamond88.6%92.9%Kimi K3
LiveBench reasoningNot measured90.7%Only Kimi K3 measured
MMMU Pro (Vals AI)83.5%88.2%Kimi K3
GPQA Diamond (Artificial Analysis run)91.1%93.5%Kimi K3
Humanity's Last Exam (Artificial Analysis run)34.5%46.9%Kimi K3
GPQA Diamond (Epoch AI run)Not measured93.1%Only Kimi K3 measured
ARC-AGI89.5%94.5%Kimi K3
ARC-AGI-265.1%60.4%Grok 4.20
SimpleBenchNot measured60.7%Only Kimi K3 measured
Chess puzzlesNot measured37.0%Only Kimi K3 measured
Mystery game puzzlesNot measured26.0%Only Kimi K3 measured
LMArena Text: hard promptsNot measured1495Only Kimi K3 measured
LMArena Text: expertNot measured1520Only Kimi K3 measured
LMArena Text: hard prompts in EnglishNot measured1496Only Kimi K3 measured
Neither model has a result on the other 7 boards here
MathDirectional onlyPublic boards, shown as published, kept out of the index7 boards, none shared
Math benchmarks for Grok 4.20 and Kimi K3
BenchmarkGrok 4.20Kimi K3Leader
AIME96.5%Not measuredOnly Grok 4.20 measured
OTIS Mock AIMENot measured97.2%Only Kimi K3 measured
FrontierMath, tiers 1 to 3Not measured72.2%Only Kimi K3 measured
FrontierMath, tier 4Not measured39.0%Only Kimi K3 measured
ProofBenchNot measured87.0%Only Kimi K3 measured
LMArena Text: mathNot measured1494Only Kimi K3 measured
LMArena Text: mathematical workNot measured1505Only Kimi K3 measured
Neither model has a result on the other 6 boards here
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index06
Knowledge benchmarks for Grok 4.20 and Kimi K3
BenchmarkGrok 4.20Kimi K3Leader
MMLU Pro86.3%88.0%Kimi K3
LegalBench (Vals AI)77.7%86.2%Kimi K3
CaseLaw (Vals AI)54.4%Not measuredOnly Grok 4.20 measured
CorpFin (Vals AI)63.7%71.6%Kimi K3
TaxEval (Vals AI)74.1%75.7%Kimi K3
MortgageTax (Vals AI)45.4%66.3%Kimi K3
MedQA (Vals AI)94.5%Not measuredOnly Grok 4.20 measured
MedCode (Vals AI)32.2%49.4%Kimi K3
SimpleQA VerifiedNot measured50.6%Only Kimi K3 measured
LMArena Text: scienceNot measured1508Only Kimi K3 measured
LMArena Text: medicine and healthcareNot measured1489Only Kimi K3 measured
LMArena Text: legal and governmentNot measured1503Only Kimi K3 measured
LMArena Text: business and financeNot measured1470Only Kimi K3 measured
Neither model has a result on the other 4 boards here
Web designLike-for-likePublic boards, shown as published, kept out of the index07
Web design benchmarks for Grok 4.20 and Kimi K3
BenchmarkGrok 4.20Kimi K3Leader
Design Arena: websites12291335Kimi K3
Design Arena: UI components11991344Kimi K3
Design Arena: game dev11921360Kimi K3
Design Arena: data viz12171350Kimi K3
Design Arena: 3D11931388Kimi K3
Design Arena: all code categories12211361Kimi K3
Design Arena: SVG11641302Kimi K3
Design Arena: ASCII art1174Not measuredOnly Grok 4.20 measured
LiveBench designNot measured77.2%Only Kimi K3 measured
GeneralLike-for-likePublic boards, shown as published, kept out of the index06
General benchmarks for Grok 4.20 and Kimi K3
BenchmarkGrok 4.20Kimi K3Leader
Vals IndexNot measured53.0%Only Kimi K3 measured
LiveBench data analysisNot measured78.7%Only Kimi K3 measured
Public Benefits Bench (Vals AI)Not measured68.2%Only Kimi K3 measured
SAGE (Vals AI)38.2%52.8%Kimi K3
MedScribe (Vals AI)63.4%88.0%Kimi K3
Vals Multimodal Index39.1%73.4%Kimi K3
IFBench81.2%Not measuredOnly Grok 4.20 measured
Long context reasoning (AA-LCR)69.0%88.7%Kimi K3
DTBench90.1%91.2%Kimi K3
LMCA38.7%52.7%Kimi K3
CL-bench22.2%Not measuredOnly Grok 4.20 measured
Surface Evolver BenchNot measured95.0%Only Kimi K3 measured
Furniture assemblyNot measured34.2%Only Kimi K3 measured
CL-bench Life11.9%Not measuredOnly Grok 4.20 measured
LMArena TextNot measured1476Only Kimi K3 measured
LMArena Text: instruction followingNot measured1485Only Kimi K3 measured
LMArena Text: creative writingNot measured1457Only Kimi K3 measured
LMArena Text: EnglishNot measured1481Only Kimi K3 measured
LMArena Text: non-EnglishNot measured1466Only Kimi K3 measured
LMArena Text: ChineseNot measured1529Only Kimi K3 measured
LMArena Text: GermanNot measured1490Only Kimi K3 measured
LMArena Text: JapaneseNot measured1494Only Kimi K3 measured
LMArena Text: KoreanNot measured1460Only Kimi K3 measured
LMArena Text: FrenchNot measured1492Only Kimi K3 measured
LMArena Text: SpanishNot measured1472Only Kimi K3 measured
LMArena Text: RussianNot measured1485Only Kimi K3 measured
LMArena Text: PolishNot measured1458Only Kimi K3 measured
LMArena Text: multi-turnNot measured1489Only Kimi K3 measured
LMArena Text: longer queriesNot measured1494Only Kimi K3 measured
LMArena Text: writing and languageNot measured1471Only Kimi K3 measured
LMArena Text: entertainment and mediaNot measured1453Only Kimi K3 measured
Neither model has a result on the other 15 boards here
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
Image generation benchmarks for Grok 4.20 and Kimi K3
BenchmarkGrok 4.20Kimi K3Leader
Neither model has a result on 5 boards here

What each workload costs

Three fixed token mixes at each model's listed price, so per-token rates become a bill.

Chat turn

1K input + 500 output tokens

Grok 4.20$0.0025Fits in one request
Kimi K3$0.011Fits in one request

Grok 4.20 costs less

Repository review

50K input + 3K output tokens

Grok 4.20$0.070Fits in one request
Kimi K3$0.195Fits in one request

Grok 4.20 costs less

Agent loop

200K input + 10K output tokens

Grok 4.20$0.275Fits in one request
Kimi K3$0.750Fits in one request

Grok 4.20 costs less

Listed OpenRouter rates, without cache or batch discounts. A workload that does not fit a model's context window would need splitting.

Specification differences

The leading value in a row is marked; a row with a missing value names no leader. Our two rows are marked in red.

Specifications of Grok 4.20 and Kimi K3
SpecificationSpaceXAI Grok 4.20MoonshotAI Kimi K3
MakerxAIMoonshot AI
WeightsNo public weights listedOpen weights
ReleasedMarch 31, 2026July 16, 2026
Context window2M1.05M
Input $/Mtok$1.25$3.00
Output $/Mtok$2.50$15.00
Coding index33.362.3
Independent measurements behind it26
Cost per solved task$0.72$0.81
SourceOpenRouter listingOpenRouter listing

Questions

Is Grok 4.20 better than Kimi K3 for coding?

Pick Kimi K3 for coding: it scores 62.3 on the Vibe Coding Index against 33.3 for Grok 4.20. Pick Grok 4.20 when output tokens cost 6.0x less, or when a solved task costs $0.72 against $0.81.

Which is cheaper, Grok 4.20 or Kimi K3?

Grok 4.20 costs $1.25 per million input tokens and $2.50 per million output tokens; Kimi K3 costs $3.00 and $15.00. Per solved SWE-bench Verified task, Grok 4.20 costs $0.72 and Kimi K3 $0.81.

Which has the bigger context window, Grok 4.20 or Kimi K3?

Grok 4.20, with 2M tokens against 1.05M.

How many benchmarks is the Grok 4.20 vs Kimi K3 comparison based on?

44 benchmarks have a result for both models as of October 21, 2026. Grok 4.20's coding index rests on 2 independent benchmarks and Kimi K3's on 6. Where only one model has a result, the page says so instead of naming a winner.

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<p style="font:13px/1.4 sans-serif;margin:6px 0 0">Source: <a href="https://llmbenchmark.ai/compare/grok-4-20-vs-kimi-k3">LLMBenchmark.ai, Grok 4.20 vs Kimi K3</a></p>