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Grok 4.20 vs Kimi K2.5

Updated October 21, 2026. 48 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 K2.5
Grok 4.20xAI
Coding
33.3
Overall
25.7
Output $/M
$2.50
22
Kimi K2.5Moonshot AI
Coding
38.6
Overall
23.5
Output $/M
$2.85
26
vs boards won of 48 shared

Decision reading

Pick Kimi K2.5 for coding: it scores 38.6 on the Vibe Coding Index against 33.3 for Grok 4.20.

Pick Grok 4.20 when output tokens cost 1.1x less, or when the context window is larger, 2M against 262K tokens.

Model AGrok 4.20xAI33.3/1002 independent benchmarks$0.72 per solved taskModel BKimi K2.5Moonshot AI38.6/1003 independent benchmarks$0.24 per solved task
Shared results
48
Grok 4.20 only
6
Kimi K2.5 only
50
Like-for-like categories
8 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 K2.5 38.6 from 3 benchmarks.
Widest category
Reasoning, 15.0 points apart on average over 6 shared benchmarks.
Widest single gap
ARC-AGI-2: Grok 4.20 65.1% against Kimi K2.5 11.8%, 53.3 points apart on a 0 to 100 scale.
Output price
Grok 4.20 $2.50 against Kimi K2.5 $2.85 per million output tokens, 1.1x apart.
Context window
Grok 4.20 takes 2M tokens, Kimi K2.5 262K.

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 K2.5Ties
Coding62
Intelligence20
Agentic work28
Reasoning51
Math10
Knowledge25
Web design26
General24
All shared boards2226
CodingLike-for-likeSix of these boards feed the Vibe Coding Index62
Coding benchmarks for Grok 4.20 and Kimi K2.5
BenchmarkGrok 4.20Kimi K2.5Leader
SWE-bench VerifiedNot measured70.8%Only Kimi K2.5 measured
SWE-bench MultilingualNot measured67.3%Only Kimi K2.5 measured
LMArena WebDevNot measured1437Only Kimi K2.5 measured
AA Coding IndexNot measured46.8Only Kimi K2.5 measured
LiveCodeBench (Vals AI)84.3%83.9%Grok 4.20
SWE-bench Verified (Vals AI)72.2%70.0%Grok 4.20
Vibe Code Bench (Vals AI)4.1%17.5%Kimi K2.5
Code migration (Vals AI)0.3%7.0%Kimi K2.5
Terminal-Bench 2.1 (Vals AI)44.2%42.0%Grok 4.20
Terminal-Bench Hard (Artificial Analysis run)37.9%34.8%Grok 4.20
Terminal-Bench57.3%43.2%Grok 4.20
WeirdML52.3%45.6%Grok 4.20
ALE-BenchNot measured821.6Only Kimi K2.5 measured
LMArena Text: codingNot measured1483Only Kimi K2.5 measured
LMArena Text: software and ITNot measured1471Only Kimi K2.5 measured
LMArena WebDev: ReactNot measured1429Only Kimi K2.5 measured
LMArena WebDev: HTMLNot measured1426Only Kimi K2.5 measured
LMArena WebDev: from an imageNot measured1439Only Kimi K2.5 measured
Neither model has a result on the other 20 boards here
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index20
Intelligence benchmarks for Grok 4.20 and Kimi K2.5
BenchmarkGrok 4.20Kimi K2.5Leader
AA Intelligence Index25.723.5Grok 4.20
Epoch Capabilities Index152.1148.1Grok 4.20
Agentic workLike-for-likePublic boards, shown as published, kept out of the index28
Agentic work benchmarks for Grok 4.20 and Kimi K2.5
BenchmarkGrok 4.20Kimi K2.5Leader
Design Arena: agents building web apps11441136Grok 4.20
Design Arena: agents building full-stack apps10541114Kimi K2.5
Design Arena: agents building mobile apps10901147Kimi K2.5
Design Arena: agents building Android apps10521125Kimi K2.5
Design Arena: agents building Godot games10891219Kimi K2.5
Design Arena: HTML slides1180Not measuredOnly Grok 4.20 measured
Finance Agent (Vals AI)28.5%35.8%Kimi K2.5
Tax Agent Bench (Vals AI)7.0%Not measuredOnly Grok 4.20 measured
Legal Research Bench (Vals AI)13.9%15.9%Kimi K2.5
Excel Modeling Benchmark (Vals AI)11.7%28.5%Kimi K2.5
τ²-Bench Telecom93.0%95.9%Kimi K2.5
OSWorldNot measured63.3%Only Kimi K2.5 measured
Vending-Bench 2$4,663$1,198Grok 4.20
Neither model has a result on the other 26 boards here
ReasoningLike-for-likePublic boards, shown as published, kept out of the index51
Reasoning benchmarks for Grok 4.20 and Kimi K2.5
BenchmarkGrok 4.20Kimi K2.5Leader
GPQA Diamond88.6%84.1%Grok 4.20
MMMU Pro (Vals AI)83.5%84.3%Kimi K2.5
GPQA Diamond (Artificial Analysis run)91.1%87.9%Grok 4.20
Humanity's Last Exam (Artificial Analysis run)34.5%30.7%Grok 4.20
ARC-AGI89.5%65.3%Grok 4.20
ARC-AGI-265.1%11.8%Grok 4.20
SimpleBenchNot measured46.8%Only Kimi K2.5 measured
LMArena Text: hard promptsNot measured1453Only Kimi K2.5 measured
LMArena Text: expertNot measured1466Only Kimi K2.5 measured
LMArena Text: hard prompts in EnglishNot measured1460Only Kimi K2.5 measured
LMArena Vision: diagramsNot measured1282Only Kimi K2.5 measured
LMArena Vision: homeworkNot measured1297Only Kimi K2.5 measured
Neither model has a result on the other 9 boards here
MathLike-for-likePublic boards, shown as published, kept out of the index10
Math benchmarks for Grok 4.20 and Kimi K2.5
BenchmarkGrok 4.20Kimi K2.5Leader
AIME96.5%95.6%Grok 4.20
LMArena Text: mathNot measured1470Only Kimi K2.5 measured
LMArena Text: mathematical workNot measured1473Only Kimi K2.5 measured
Neither model has a result on the other 10 boards here
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index25
Knowledge benchmarks for Grok 4.20 and Kimi K2.5
BenchmarkGrok 4.20Kimi K2.5Leader
MMLU Pro86.3%85.9%Grok 4.20
LegalBench (Vals AI)77.7%Not measuredOnly Grok 4.20 measured
CaseLaw (Vals AI)54.4%58.7%Kimi K2.5
CorpFin (Vals AI)63.7%68.3%Kimi K2.5
TaxEval (Vals AI)74.1%74.2%Kimi K2.5
MortgageTax (Vals AI)45.4%66.5%Kimi K2.5
MedQA (Vals AI)94.5%94.4%Grok 4.20
MedCode (Vals AI)32.2%39.3%Kimi K2.5
SimpleQA VerifiedNot measured34.3%Only Kimi K2.5 measured
LMArena Text: scienceNot measured1459Only Kimi K2.5 measured
LMArena Text: medicine and healthcareNot measured1448Only Kimi K2.5 measured
LMArena Text: legal and governmentNot measured1441Only Kimi K2.5 measured
LMArena Text: business and financeNot measured1427Only Kimi K2.5 measured
Neither model has a result on the other 4 boards here
Web designLike-for-likePublic boards, shown as published, kept out of the index26
Web design benchmarks for Grok 4.20 and Kimi K2.5
BenchmarkGrok 4.20Kimi K2.5Leader
Design Arena: websites12291249Kimi K2.5
Design Arena: UI components11991236Kimi K2.5
Design Arena: game dev11921207Kimi K2.5
Design Arena: data viz12171218Kimi K2.5
Design Arena: 3D11931205Kimi K2.5
Design Arena: all code categories12211236Kimi K2.5
Design Arena: SVG11641149Grok 4.20
Design Arena: ASCII art11741165Grok 4.20
Neither model has a result on the other 1 board here
GeneralLike-for-likePublic boards, shown as published, kept out of the index24
General benchmarks for Grok 4.20 and Kimi K2.5
BenchmarkGrok 4.20Kimi K2.5Leader
SAGE (Vals AI)38.2%49.9%Kimi K2.5
MedScribe (Vals AI)63.4%76.4%Kimi K2.5
Vals Multimodal Index39.1%Not measuredOnly Grok 4.20 measured
IFBench81.2%70.2%Grok 4.20
Long context reasoning (AA-LCR)69.0%78.0%Kimi K2.5
DTBench90.1%Not measuredOnly Grok 4.20 measured
LMCA38.7%Not measuredOnly Grok 4.20 measured
Fiction.LiveBenchNot measured86.1%Only Kimi K2.5 measured
CL-bench22.2%19.3%Grok 4.20
CL-bench Life11.9%13.2%Kimi K2.5
LMArena TextNot measured1445Only Kimi K2.5 measured
LMArena Text: instruction followingNot measured1431Only Kimi K2.5 measured
LMArena Text: creative writingNot measured1422Only Kimi K2.5 measured
LMArena VisionNot measured1269Only Kimi K2.5 measured
LMArena Text: EnglishNot measured1453Only Kimi K2.5 measured
LMArena Text: non-EnglishNot measured1433Only Kimi K2.5 measured
LMArena Text: ChineseNot measured1494Only Kimi K2.5 measured
LMArena Text: GermanNot measured1441Only Kimi K2.5 measured
LMArena Text: JapaneseNot measured1423Only Kimi K2.5 measured
LMArena Text: KoreanNot measured1412Only Kimi K2.5 measured
LMArena Text: FrenchNot measured1454Only Kimi K2.5 measured
LMArena Text: SpanishNot measured1450Only Kimi K2.5 measured
LMArena Text: RussianNot measured1435Only Kimi K2.5 measured
LMArena Text: PolishNot measured1445Only Kimi K2.5 measured
LMArena Text: multi-turnNot measured1444Only Kimi K2.5 measured
LMArena Text: longer queriesNot measured1445Only Kimi K2.5 measured
LMArena Text: writing and languageNot measured1425Only Kimi K2.5 measured
LMArena Text: entertainment and mediaNot measured1417Only Kimi K2.5 measured
LMArena Vision: EnglishNot measured1274Only Kimi K2.5 measured
LMArena Vision: ChineseNot measured1328Only Kimi K2.5 measured
LMArena Vision: reading textNot measured1276Only Kimi K2.5 measured
LMArena Vision: humorNot measured1284Only Kimi K2.5 measured
LMArena Vision: captioningNot measured1257Only Kimi K2.5 measured
LMArena Vision: recognizing thingsNot measured1285Only Kimi K2.5 measured
LMArena Vision: creative writingNot measured1269Only Kimi K2.5 measured
Neither model has a result on the other 11 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 K2.5
BenchmarkGrok 4.20Kimi K2.5Leader
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 K2.5$0.0020Fits in one request

Kimi K2.5 costs less

Repository review

50K input + 3K output tokens

Grok 4.20$0.070Fits in one request
Kimi K2.5$0.035Fits in one request

Kimi K2.5 costs less

Agent loop

200K input + 10K output tokens

Grok 4.20$0.275Fits in one request
Kimi K2.5$0.135Fits in one request

Kimi K2.5 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 K2.5
SpecificationSpaceXAI Grok 4.20MoonshotAI Kimi K2.5
MakerxAIMoonshot AI
WeightsNo public weights listedOpen weights
ReleasedMarch 31, 2026January 27, 2026
Context window2M262K
Input $/Mtok$1.25$0.532
Output $/Mtok$2.50$2.85
Coding index33.338.6
Independent measurements behind it23
Cost per solved task$0.72$0.24
SourceOpenRouter listingOpenRouter listing

Questions

Is Grok 4.20 better than Kimi K2.5 for coding?

Pick Kimi K2.5 for coding: it scores 38.6 on the Vibe Coding Index against 33.3 for Grok 4.20. Pick Grok 4.20 when output tokens cost 1.1x less, or when the context window is larger, 2M against 262K tokens.

Which is cheaper, Grok 4.20 or Kimi K2.5?

Grok 4.20 costs $1.25 per million input tokens and $2.50 per million output tokens; Kimi K2.5 costs $0.532 and $2.85. Per solved SWE-bench Verified task, Grok 4.20 costs $0.72 and Kimi K2.5 $0.24.

Which has the bigger context window, Grok 4.20 or Kimi K2.5?

Grok 4.20, with 2M tokens against 262K.

How many benchmarks is the Grok 4.20 vs Kimi K2.5 comparison based on?

48 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 K2.5's on 3. 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-k2-5">LLMBenchmark.ai, Grok 4.20 vs Kimi K2.5</a></p>