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Kimi K3 vs o3

Updated October 21, 2026. 62 benchmarks have a result for both. Coding is ranked on the Vibe Coding Index; every other board is shown as published.

Replace Kimi K3 Replace o3
Kimi K3Moonshot AI
Coding
61.8
Overall
43.6
Output $/M
$11.936
60
o3OpenAI
Coding
70.7
Overall
20.2
Output $/M
$8.00
1
vs boards won of 62 shared, 1 tied

Decision reading

Pick o3 for coding: it scores 70.7 on the Vibe Coding Index against 61.8 for Kimi K3.

Pick Kimi K3 when the context window is larger, 1.05M against 200K tokens, or when what matters is LiveCodeBench (Vals AI) or WeirdML, where it leads.

Model AKimi K3Moonshot AI61.8/1002 independent benchmarks$0.81 per solved taskModel Bo3OpenAI70.7/1002 independent benchmarks$0.571 per solved task
Shared results
62
Kimi K3 only
55
o3 only
35
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
Kimi K3 61.8 from 2 benchmarks, o3 70.7 from 2 benchmarks.
Widest category
Web design, 36.1 points apart on average over 5 shared benchmarks.
Widest single gap
ARC-AGI-2: Kimi K3 60.4% against o3 6.5%, 53.9 points apart on a 0 to 100 scale.
Output price
Kimi K3 $11.936 against o3 $8.00 per million output tokens, 1.5x apart.
Context window
Kimi K3 takes 1.05M tokens, o3 200K.

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
CategoryKimi K3Barso3Ties
Coding50
Intelligence20
Reasoning1111 tie
Math40
Knowledge110
Web design50
General220
All shared boards6011 tie
CodingLike-for-likeFour of these boards feed the Vibe Coding Index50
Coding benchmarks for Kimi K3 and o3
BenchmarkKimi K3o3Leader
Aider polyglotNot measured81.3%Only o3 measured
SWE-bench VerifiedNot measured58.4%Only o3 measured
SWE-bench MultimodalNot measured36.0%Only o3 measured
LiveBench coding59.3%Not measuredOnly Kimi K3 measured
LMArena WebDev1655Not measuredOnly Kimi K3 measured
AA Coding Index76.2Not measuredOnly Kimi K3 measured
LiveCodeBench (Vals AI)87.2%83.9%Kimi K3
SWE-bench Verified (Vals AI)93.4%Not measuredOnly Kimi K3 measured
Terminal-Bench 4 (Vals AI)17.2%Not measuredOnly Kimi K3 measured
Vibe Code Bench (Vals AI)85.0%Not measuredOnly Kimi K3 measured
Code migration (Vals AI)16.1%Not measuredOnly Kimi K3 measured
ProgramBench (Vals AI)2.0%Not measuredOnly Kimi K3 measured
IOI (Vals AI)48.9%Not measuredOnly Kimi K3 measured
Terminal-Bench 2.1 (Vals AI)80.9%Not measuredOnly Kimi K3 measured
SWE-bench Multimodal (Vals AI)44.2%Not measuredOnly Kimi K3 measured
Vibe Code Bench 1-100 (Vals AI)18.2%Not measuredOnly Kimi K3 measured
CyberBench (Vals AI)75.2%Not measuredOnly Kimi K3 measured
LiveCodeBench (Artificial Analysis run)Not measured80.8%Only o3 measured
SciCode59.5%Not measuredOnly Kimi K3 measured
Terminal-Bench Hard (Artificial Analysis run)Not measured37.1%Only o3 measured
FrontierCode44.2%Not measuredOnly Kimi K3 measured
FrontierSWE25.9%Not measuredOnly Kimi K3 measured
GSO-BenchNot measured8.8%Only o3 measured
WeirdML82.6%52.4%Kimi K3
ALE-Bench1524.5933.5Kimi K3
LMArena Text: coding15081407Kimi K3
LMArena Text: software and IT14991415Kimi K3
LMArena WebDev: React1670Not measuredOnly Kimi K3 measured
LMArena WebDev: HTML1644Not measuredOnly Kimi K3 measured
LMArena WebDev: from an image1579Not measuredOnly Kimi K3 measured
Neither model has a result on the other 8 boards here
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index20
Intelligence benchmarks for Kimi K3 and o3
BenchmarkKimi K3o3Leader
AA Intelligence Index43.620.2Kimi K3
Epoch Capabilities Index157.9146.7Kimi K3
Agentic workDirectional onlyPublic boards, shown as published, kept out of the index29 boards, none shared
Agentic work benchmarks for Kimi K3 and o3
BenchmarkKimi K3o3Leader
AA Agentic Index50.0Not measuredOnly Kimi K3 measured
Design Arena: agents building web apps1296Not measuredOnly Kimi K3 measured
Design Arena: agents building full-stack apps1315Not measuredOnly Kimi K3 measured
Design Arena: agents building mobile apps1267Not measuredOnly Kimi K3 measured
Design Arena: agents building Android apps1256Not measuredOnly Kimi K3 measured
Design Arena: agents building Godot games1223Not measuredOnly Kimi K3 measured
Design Arena: agents building games1252Not measuredOnly Kimi K3 measured
Design Arena: HTML slides1256Not measuredOnly Kimi K3 measured
Design Arena: PowerPoint slides1273Not measuredOnly Kimi K3 measured
Design Arena: spreadsheets1058Not measuredOnly Kimi K3 measured
LiveBench research79.0%Not measuredOnly Kimi K3 measured
LiveBench browser16.0%Not measuredOnly Kimi K3 measured
LiveBench long agentic42.8%Not measuredOnly Kimi K3 measured
Finance Agent (Vals AI)53.1%Not measuredOnly Kimi K3 measured
Tax Agent Bench (Vals AI)33.4%Not measuredOnly Kimi K3 measured
Legal Research Bench (Vals AI)46.1%Not measuredOnly Kimi K3 measured
Harvey's Legal Agent Benchmark (Vals AI)12.9%Not measuredOnly Kimi K3 measured
Excel Modeling Benchmark (Vals AI)66.7%Not measuredOnly Kimi K3 measured
BioMysteryBench (Vals AI)72.6%Not measuredOnly Kimi K3 measured
Terminal-Bench-Science (Vals AI)1.4%Not measuredOnly Kimi K3 measured
Time Horizon Index (Vals AI)10.5%Not measuredOnly Kimi K3 measured
τ²-Bench TelecomNot measured80.7%Only o3 measured
APEX-Agents47.8%Not measuredOnly Kimi K3 measured
METR time horizonsNot measured65.4%Only o3 measured
GDPvalNot measured30.8%Only o3 measured
DeepResearch BenchNot measured45.2%Only o3 measured
PostTrainBench32.0%Not measuredOnly Kimi K3 measured
OSWorldNot measured23.0%Only o3 measured
Vending-Bench 2$5,165Not measuredOnly Kimi K3 measured
Neither model has a result on the other 10 boards here
ReasoningLike-for-likePublic boards, shown as published, kept out of the index111
Reasoning benchmarks for Kimi K3 and o3
BenchmarkKimi K3o3Leader
GPQA Diamond92.9%84.1%Kimi K3
LiveBench reasoning90.7%Not measuredOnly Kimi K3 measured
MMMU Pro (Vals AI)88.2%80.4%Kimi K3
GPQA Diamond (Artificial Analysis run)93.5%82.7%Kimi K3
Humanity's Last Exam (Artificial Analysis run)46.9%20.1%Kimi K3
GPQA Diamond (Epoch AI run)93.1%81.8%Kimi K3
ARC-AGI94.5%60.8%Kimi K3
ARC-AGI-260.4%6.5%Kimi K3
SimpleBench60.7%53.1%Kimi K3
Chess puzzles37.0%37.0%Tie
Mystery game puzzles26.0%29.0%o3
VPCTNot measured52.0%Only o3 measured
LMArena Text: hard prompts14951402Kimi K3
LMArena Text: expert15201402Kimi K3
LMArena Text: hard prompts in English14961411Kimi K3
LMArena Vision: diagramsNot measured1220Only o3 measured
LMArena Vision: homeworkNot measured1234Only o3 measured
Neither model has a result on the other 4 boards here
MathLike-for-likePublic boards, shown as published, kept out of the index40
Math benchmarks for Kimi K3 and o3
BenchmarkKimi K3o3Leader
AIMENot measured85.3%Only o3 measured
MATH 500 (Vals AI)Not measured94.6%Only o3 measured
MGSM (Vals AI)Not measured91.8%Only o3 measured
AA Math IndexNot measured88.3Only o3 measured
AIME 2025 (Artificial Analysis run)Not measured88.3%Only o3 measured
OTIS Mock AIME97.2%84.4%Kimi K3
FrontierMath, tiers 1 to 372.2%33.3%Kimi K3
FrontierMath, tier 439.0%Not measuredOnly Kimi K3 measured
ProofBench87.0%Not measuredOnly Kimi K3 measured
MATH level 5Not measured97.8%Only o3 measured
LMArena Text: math14941426Kimi K3
LMArena Text: mathematical work15051423Kimi K3
Neither model has a result on the other 1 board here
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index110
Knowledge benchmarks for Kimi K3 and o3
BenchmarkKimi K3o3Leader
MMLU Pro88.0%85.6%Kimi K3
LegalBench (Vals AI)86.2%83.8%Kimi K3
CorpFin (Vals AI)71.6%59.7%Kimi K3
TaxEval (Vals AI)75.7%74.6%Kimi K3
MortgageTax (Vals AI)66.3%65.7%Kimi K3
MedQA (Vals AI)Not measured96.1%Only o3 measured
MedCode (Vals AI)49.4%47.3%Kimi K3
MMLU Pro (Artificial Analysis run)Not measured85.3%Only o3 measured
SimpleQA Verified50.6%49.4%Kimi K3
GeoBenchNot measured74.0%Only o3 measured
LMArena Text: science15081429Kimi K3
LMArena Text: medicine and healthcare14891448Kimi K3
LMArena Text: legal and government15031428Kimi K3
LMArena Text: business and finance14701393Kimi K3
Neither model has a result on the other 3 boards here
Web designLike-for-likePublic boards, shown as published, kept out of the index50
Web design benchmarks for Kimi K3 and o3
BenchmarkKimi K3o3Leader
Design Arena: websites13361036Kimi K3
Design Arena: UI components13451016Kimi K3
Design Arena: game dev13611034Kimi K3
Design Arena: data viz13501200Kimi K3
Design Arena: 3D1388Not measuredOnly Kimi K3 measured
Design Arena: all code categories13611021Kimi K3
Design Arena: SVG1301Not measuredOnly Kimi K3 measured
LiveBench design77.2%Not measuredOnly Kimi K3 measured
Neither model has a result on the other 1 board here
GeneralLike-for-likePublic boards, shown as published, kept out of the index220
General benchmarks for Kimi K3 and o3
BenchmarkKimi K3o3Leader
Vals Index53.0%Not measuredOnly Kimi K3 measured
LiveBench data analysis78.7%Not measuredOnly Kimi K3 measured
Public Benefits Bench (Vals AI)68.2%Not measuredOnly Kimi K3 measured
SAGE (Vals AI)52.8%41.8%Kimi K3
MedScribe (Vals AI)88.0%76.7%Kimi K3
Vals Multimodal Index73.4%Not measuredOnly Kimi K3 measured
IFBenchNot measured71.4%Only o3 measured
Long context reasoning (AA-LCR)88.7%74.7%Kimi K3
DTBench91.2%84.8%Kimi K3
LMCA52.7%39.7%Kimi K3
Fiction.LiveBenchNot measured88.9%Only o3 measured
Creative writing (Lech Mazur)Not measured83.9%Only o3 measured
CL-benchNot measured17.8%Only o3 measured
Surface Evolver Bench95.0%Not measuredOnly Kimi K3 measured
Furniture assembly34.2%Not measuredOnly Kimi K3 measured
LMArena Text14761410Kimi K3
LMArena Text: instruction following14851368Kimi K3
LMArena Text: creative writing14571359Kimi K3
LMArena VisionNot measured1214Only o3 measured
LMArena Text: English14811417Kimi K3
LMArena Text: non-English14661401Kimi K3
LMArena Text: Chinese15291437Kimi K3
LMArena Text: German14901420Kimi K3
LMArena Text: Japanese14941403Kimi K3
LMArena Text: Korean14601370Kimi K3
LMArena Text: French14921430Kimi K3
LMArena Text: Spanish14721395Kimi K3
LMArena Text: Russian14851406Kimi K3
LMArena Text: Polish14581438Kimi K3
LMArena Text: multi-turn14891405Kimi K3
LMArena Text: longer queries14941372Kimi K3
LMArena Text: writing and language14711372Kimi K3
LMArena Text: entertainment and media14531373Kimi K3
LMArena Vision: EnglishNot measured1221Only o3 measured
LMArena Vision: ChineseNot measured1237Only o3 measured
LMArena Vision: reading textNot measured1218Only o3 measured
LMArena Vision: humorNot measured1222Only o3 measured
LMArena Vision: captioningNot measured1210Only o3 measured
LMArena Vision: recognizing thingsNot measured1234Only o3 measured
LMArena Vision: creative writingNot measured1201Only o3 measured
Neither model has a result on the other 6 boards here
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
Image generation benchmarks for Kimi K3 and o3
BenchmarkKimi K3o3Leader
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

Kimi K3$0.0062Fits in one request
o3$0.0060Fits in one request

o3 costs less

Repository review

50K input + 3K output tokens

Kimi K3$0.048Fits in one request
o3$0.124Fits in one request

Kimi K3 costs less

Agent loop

200K input + 10K output tokens

Kimi K3$0.167Fits in one request
o3$0.480Exceeds the context window

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 Kimi K3 and o3
SpecificationMoonshotAI Kimi K3OpenAI o3
MakerMoonshot AIOpenAI
WeightsOpen weightsNo public weights listed
ReleasedJuly 16, 2026April 16, 2025
Context window1.05M200K
Input $/Mtok$0.239$2.00
Output $/Mtok$11.936$8.00
Coding index61.870.7
Independent measurements behind it22
Cost per solved task$0.81$0.571
SourceOpenRouter listingOpenRouter listing

Questions

Is Kimi K3 better than o3 for coding?

Pick o3 for coding: it scores 70.7 on the Vibe Coding Index against 61.8 for Kimi K3. Pick Kimi K3 when the context window is larger, 1.05M against 200K tokens, or when what matters is LiveCodeBench (Vals AI) or WeirdML, where it leads.

Which is cheaper, Kimi K3 or o3?

Kimi K3 costs $0.239 per million input tokens and $11.936 per million output tokens; o3 costs $2.00 and $8.00. Per solved SWE-bench Verified task, Kimi K3 costs $0.81 and o3 $0.571.

Which has the bigger context window, Kimi K3 or o3?

Kimi K3, with 1.05M tokens against 200K.

How many benchmarks is the Kimi K3 vs o3 comparison based on?

62 benchmarks have a result for both models as of October 21, 2026. Kimi K3's coding index rests on 2 independent benchmarks and o3's on 2. Where only one model has a result, the page says so instead of naming a winner.

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