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Grok 4.5 vs Kimi K3

Updated October 21, 2026. 107 benchmarks have a result for both. Coding is ranked on the Vibe Coding Index; every other board is shown as published.

Replace Grok 4.5 Replace Kimi K3
Grok 4.5xAI
Coding
75.5
Overall
38.8
Output $/M
$6.00
13
Kimi K3Moonshot AI
Coding
61.8
Overall
43.6
Output $/M
$11.936
93
vs boards won of 107 shared, 1 tied

Decision reading

Pick Grok 4.5 for coding: it scores 75.5 on the Vibe Coding Index against 61.8 for Kimi K3.

Pick Kimi K3 when the context window is larger, 1.05M against 500K tokens, or when what matters is LMArena WebDev or AA Coding Index, where it leads.

Model AGrok 4.5xAI75.5/1002 independent benchmarks$0.62 per solved taskModel BKimi K3Moonshot AI61.8/1002 independent benchmarks$0.81 per solved task
Shared results
107
Grok 4.5 only
13
Kimi K3 only
10
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 4.5 75.5 from 2 benchmarks, Kimi K3 61.8 from 2 benchmarks.
Widest category
Math, 16.0 points apart on average over 6 shared benchmarks.
Widest single gap
ProofBench: Grok 4.5 31.0% against Kimi K3 87.0%, 56.0 points apart on a 0 to 100 scale.
Output price
Grok 4.5 $6.00 against Kimi K3 $11.936 per million output tokens, 2.0x apart.
Context window
Grok 4.5 takes 500K 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 4.5BarsKimi K3Ties
Coding318
Intelligence02
Agentic work416
Reasoning2101 tie
Math15
Knowledge110
Web design17
General125
All shared boards13931 tie
CodingLike-for-likeFour of these boards feed the Vibe Coding Index318
Coding benchmarks for Grok 4.5 and Kimi K3
BenchmarkGrok 4.5Kimi K3Leader
LiveBench coding94.3%59.3%Grok 4.5
LMArena WebDev15531655Kimi K3
AA Coding Index72.476.2Kimi K3
LiveCodeBench (Vals AI)87.3%87.2%Grok 4.5
SWE-bench Verified (Vals AI)86.6%93.4%Kimi K3
Terminal-Bench 4 (Vals AI)8.6%17.2%Kimi K3
Vibe Code Bench (Vals AI)69.0%85.0%Kimi K3
Code migration (Vals AI)36.6%16.1%Grok 4.5
ProgramBench (Vals AI)0.0%2.0%Kimi K3
IOI (Vals AI)40.6%48.9%Kimi K3
Terminal-Bench 2.1 (Vals AI)67.8%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
SkillsBench (Vals AI)66.0%Not measuredOnly Grok 4.5 measured
CyberBench (Vals AI)71.0%75.2%Kimi K3
SciCode55.0%59.5%Kimi K3
FrontierCode42.4%44.2%Kimi K3
FrontierSWENot measured25.9%Only Kimi K3 measured
WeirdML46.4%82.6%Kimi K3
ALE-Bench1309.31524.5Kimi K3
LMArena Text: coding14741508Kimi K3
LMArena Text: software and IT14711499Kimi K3
LMArena WebDev: React15561670Kimi K3
LMArena WebDev: HTML15671644Kimi K3
LMArena WebDev: from an image15621579Kimi K3
Neither model has a result on the other 13 boards here
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index02
Intelligence benchmarks for Grok 4.5 and Kimi K3
BenchmarkGrok 4.5Kimi K3Leader
AA Intelligence Index38.843.6Kimi K3
Epoch Capabilities Index154.1157.9Kimi K3
Agentic workLike-for-likePublic boards, shown as published, kept out of the index416
Agentic work benchmarks for Grok 4.5 and Kimi K3
BenchmarkGrok 4.5Kimi K3Leader
AA Agentic Index41.250.0Kimi K3
Design Arena: agents building web apps12171296Kimi K3
Design Arena: agents building full-stack apps12491315Kimi K3
Design Arena: agents building mobile apps12211267Kimi K3
Design Arena: agents building Android apps12421256Kimi K3
Design Arena: agents building Godot games12291223Grok 4.5
Design Arena: agents building games12351252Kimi K3
Design Arena: HTML slides12041256Kimi K3
Design Arena: PowerPoint slides12321273Kimi K3
Design Arena: spreadsheetsNot measured1058Only Kimi K3 measured
LiveBench research85.9%79.0%Grok 4.5
LiveBench browser44.0%16.0%Grok 4.5
LiveBench long agentic27.9%42.8%Kimi K3
SREBench (Vals AI)0.8%Not measuredOnly Grok 4.5 measured
Finance Agent (Vals AI)48.4%53.1%Kimi K3
Tax Agent Bench (Vals AI)24.9%33.4%Kimi K3
Legal Research Bench (Vals AI)38.0%46.1%Kimi K3
Harvey's Legal Agent Benchmark (Vals AI)Not measured12.9%Only Kimi K3 measured
Excel Modeling Benchmark (Vals AI)52.9%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)6.3%10.5%Kimi K3
APEX-Agents56.2%47.8%Grok 4.5
PostTrainBench23.4%32.0%Kimi K3
Vending-Bench 2$3,887$5,165Kimi K3
LMArena Search1216Not measuredOnly Grok 4.5 measured
Neither model has a result on the other 13 boards here
ReasoningLike-for-likePublic boards, shown as published, kept out of the index210
Reasoning benchmarks for Grok 4.5 and Kimi K3
BenchmarkGrok 4.5Kimi K3Leader
GPQA Diamond92.9%92.9%Tie
LiveBench reasoning87.2%90.7%Kimi K3
MMMU Pro (Vals AI)61.8%88.2%Kimi K3
GPQA Diamond (Artificial Analysis run)93.1%93.5%Kimi K3
Humanity's Last Exam (Artificial Analysis run)42.7%46.9%Kimi K3
GPQA Diamond (Epoch AI run)93.4%93.1%Grok 4.5
ARC-AGI87.2%94.5%Kimi K3
ARC-AGI-252.6%60.4%Kimi K3
SimpleBench70.0%60.7%Grok 4.5
Chess puzzles35.0%37.0%Kimi K3
Mystery game puzzlesNot measured26.0%Only Kimi K3 measured
LMArena Text: hard prompts14621495Kimi K3
LMArena Text: expert14651520Kimi K3
LMArena Text: hard prompts in English14641496Kimi K3
LMArena Vision: diagrams1304Not measuredOnly Grok 4.5 measured
LMArena Vision: homework1295Not measuredOnly Grok 4.5 measured
Neither model has a result on the other 5 boards here
MathLike-for-likePublic boards, shown as published, kept out of the index15
Math benchmarks for Grok 4.5 and Kimi K3
BenchmarkGrok 4.5Kimi K3Leader
OTIS Mock AIME97.8%97.2%Grok 4.5
FrontierMath, tiers 1 to 357.2%72.2%Kimi K3
FrontierMath, tier 424.4%39.0%Kimi K3
ProofBench31.0%87.0%Kimi K3
LMArena Text: math14601494Kimi K3
LMArena Text: mathematical work14821505Kimi K3
Neither model has a result on the other 7 boards here
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index110
Knowledge benchmarks for Grok 4.5 and Kimi K3
BenchmarkGrok 4.5Kimi K3Leader
MMLU Pro89.2%88.0%Grok 4.5
LegalBench (Vals AI)86.0%86.2%Kimi K3
CorpFin (Vals AI)67.4%71.6%Kimi K3
TaxEval (Vals AI)71.7%75.7%Kimi K3
MortgageTax (Vals AI)61.8%66.3%Kimi K3
MedCode (Vals AI)43.3%49.4%Kimi K3
SimpleQA Verified48.3%50.6%Kimi K3
LMArena Text: science14641508Kimi K3
LMArena Text: medicine and healthcare14401489Kimi K3
LMArena Text: legal and government14631503Kimi K3
LMArena Text: business and finance14411470Kimi K3
Neither model has a result on the other 6 boards here
Web designLike-for-likePublic boards, shown as published, kept out of the index17
Web design benchmarks for Grok 4.5 and Kimi K3
BenchmarkGrok 4.5Kimi K3Leader
Design Arena: websites12811336Kimi K3
Design Arena: UI components12791345Kimi K3
Design Arena: game dev12631361Kimi K3
Design Arena: data viz12671350Kimi K3
Design Arena: 3D12571388Kimi K3
Design Arena: all code categories12761361Kimi K3
Design Arena: SVG12151301Kimi K3
Design Arena: ASCII art1257Not measuredOnly Grok 4.5 measured
LiveBench design78.1%77.2%Grok 4.5
GeneralLike-for-likePublic boards, shown as published, kept out of the index125
General benchmarks for Grok 4.5 and Kimi K3
BenchmarkGrok 4.5Kimi K3Leader
Vals IndexNot measured53.0%Only Kimi K3 measured
LiveBench data analysis73.0%78.7%Kimi K3
Public Benefits Bench (Vals AI)Not measured68.2%Only Kimi K3 measured
SAGE (Vals AI)35.0%52.8%Kimi K3
MedScribe (Vals AI)86.9%88.0%Kimi K3
Vals Multimodal Index63.4%73.4%Kimi K3
Long context reasoning (AA-LCR)79.3%88.7%Kimi K3
DTBench96.5%91.2%Grok 4.5
LMCA45.2%52.7%Kimi K3
Surface Evolver Bench74.4%95.0%Kimi K3
Furniture assembly22.5%34.2%Kimi K3
LMArena Text14481476Kimi K3
LMArena Text: instruction following14451485Kimi K3
LMArena Text: creative writing14421457Kimi K3
LMArena Vision1287Not measuredOnly Grok 4.5 measured
LMArena Text: English14531481Kimi K3
LMArena Text: non-English14401466Kimi K3
LMArena Text: Chinese14951529Kimi K3
LMArena Text: German14481490Kimi K3
LMArena Text: Japanese14301494Kimi K3
LMArena Text: Korean14061460Kimi K3
LMArena Text: French14571492Kimi K3
LMArena Text: Spanish14511472Kimi K3
LMArena Text: Russian14491485Kimi K3
LMArena Text: Polish14321458Kimi K3
LMArena Text: multi-turn14561489Kimi K3
LMArena Text: longer queries14621494Kimi K3
LMArena Text: writing and language14451471Kimi K3
LMArena Text: entertainment and media14341453Kimi K3
LMArena Vision: English1285Not measuredOnly Grok 4.5 measured
LMArena Vision: Chinese1345Not measuredOnly Grok 4.5 measured
LMArena Vision: reading text1293Not measuredOnly Grok 4.5 measured
LMArena Vision: humor1276Not measuredOnly Grok 4.5 measured
LMArena Vision: creative writing1293Not measuredOnly Grok 4.5 measured
LMArena Document1452Not measuredOnly Grok 4.5 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 4.5 and Kimi K3
BenchmarkGrok 4.5Kimi 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 4.5$0.0050Fits in one request
Kimi K3$0.0062Fits in one request

Grok 4.5 costs less

Repository review

50K input + 3K output tokens

Grok 4.5$0.118Fits in one request
Kimi K3$0.048Fits in one request

Kimi K3 costs less

Agent loop

200K input + 10K output tokens

Grok 4.5$0.460Fits in one request
Kimi K3$0.167Fits in one request

Kimi K3 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 4.5 and Kimi K3
SpecificationSpaceXAI Grok 4.5MoonshotAI Kimi K3
MakerxAIMoonshot AI
WeightsNo public weights listedOpen weights
ReleasedJuly 8, 2026July 16, 2026
Context window500K1.05M
Input $/Mtok$2.00$0.239
Output $/Mtok$6.00$11.936
Coding index75.561.8
Independent measurements behind it22
Cost per solved task$0.62$0.81
SourceOpenRouter listingOpenRouter listing

Questions

Is Grok 4.5 better than Kimi K3 for coding?

Pick Grok 4.5 for coding: it scores 75.5 on the Vibe Coding Index against 61.8 for Kimi K3. Pick Kimi K3 when the context window is larger, 1.05M against 500K tokens, or when what matters is LMArena WebDev or AA Coding Index, where it leads.

Which is cheaper, Grok 4.5 or Kimi K3?

Grok 4.5 costs $2.00 per million input tokens and $6.00 per million output tokens; Kimi K3 costs $0.239 and $11.936. Per solved SWE-bench Verified task, Grok 4.5 costs $0.62 and Kimi K3 $0.81.

Which has the bigger context window, Grok 4.5 or Kimi K3?

Kimi K3, with 1.05M tokens against 500K.

How many benchmarks is the Grok 4.5 vs Kimi K3 comparison based on?

107 benchmarks have a result for both models as of October 21, 2026. Grok 4.5's coding index rests on 2 independent benchmarks and Kimi K3's on 2. Where only one model has a result, the page says so instead of naming a winner.

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