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GPT-5.3-Codex vs Kimi K2.6

GPT-5.3-Codex leads Kimi K2.6 on coding, 60.0 to 52.1 on the Vibe Coding Index, and Kimi K2.6 costs 3.5x less per output token ($4.00 vs $14.00 per million). Updated October 22, 2026; 31 benchmarks have a result for both.

Replace GPT-5.3-Codex Replace Kimi K2.6
GPT-5.3-CodexOpenAI
Coding
60.0
Overall
No data
Output $/M
$14.00
12
Kimi K2.6Moonshot AI
Coding
52.1
Overall
60.5
Output $/M
$4.00
19
vs boards won of 31 shared

GPT-5.3-Codex or Kimi K2.6: which to pick

Pick GPT-5.3-Codex for coding: it scores 60.0 on the Vibe Coding Index against 52.1 for Kimi K2.6.

Pick Kimi K2.6 for output tokens 3.5x cheaper ($4.00 vs $14.00 per million) and a lower cost per solved task ($0.35 against $0.59).

Model AGPT-5.3-CodexOpenAI60.0/1003 independent benchmarks$0.59 per solved taskModel BKimi K2.6Moonshot AI52.1/1003 independent benchmarks$0.35 per solved task
Shared results
31
GPT-5.3-Codex only
3
Kimi K2.6 only
78
Like-for-like categories
6 of 9

Only benchmarks that tested both models count toward a pick; a result only one model has is shown but not compared.

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
GPT-5.3-Codex 60.0 from 3 benchmarks, Kimi K2.6 52.1 from 3 benchmarks.
Widest category
Web design, 13.5 points apart on average over 8 shared benchmarks.
Widest single gap
Design Arena: 3D: GPT-5.3-Codex 1007 against Kimi K2.6 1267, 32.5 points apart on a 0 to 100 scale.
Output price
GPT-5.3-Codex $14.00 against Kimi K2.6 $4.00 per million output tokens, 3.5x apart.
Context window
GPT-5.3-Codex takes 400K tokens, Kimi K2.6 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
CategoryGPT-5.3-CodexBarsKimi K2.6Ties
Coding64
Intelligence20
Agentic work16
Reasoning20
Web design08
General11
All shared boards1219
CodingLike-for-likeSix of these boards feed the Vibe Coding Index64
Coding benchmarks for GPT-5.3-Codex and Kimi K2.6
BenchmarkGPT-5.3-CodexKimi K2.6Leader
LMArena WebDev14071509Kimi K2.6
AA Coding IndexNot measured61.8Only Kimi K2.6 measured
LiveCodeBench (Vals AI)87.3%86.8%GPT-5.3-Codex
SWE-bench Verified (Vals AI)78.0%76.2%GPT-5.3-Codex
Vibe Code Bench (Vals AI)61.8%37.9%GPT-5.3-Codex
Code migration (Vals AI)Not measured27.8%Only Kimi K2.6 measured
ProgramBench (Vals AI)Not measured0.0%Only Kimi K2.6 measured
IOI (Vals AI)53.8%Not measuredOnly GPT-5.3-Codex measured
Terminal-Bench 2.1 (Vals AI)Not measured53.6%Only Kimi K2.6 measured
SciCodeNot measured51.5%Only Kimi K2.6 measured
Terminal-Bench Hard (Artificial Analysis run)53.0%43.9%GPT-5.3-Codex
Terminal-Bench78.4%Not measuredOnly GPT-5.3-Codex measured
WeirdML79.3%55.9%GPT-5.3-Codex
ALE-Bench1655.21092.7GPT-5.3-Codex
LMArena Text: codingNot measured1489Only Kimi K2.6 measured
LMArena Text: software and ITNot measured1484Only Kimi K2.6 measured
LMArena WebDev: React13951505Kimi K2.6
LMArena WebDev: HTML14221485Kimi K2.6
LMArena WebDev: from an image14431521Kimi K2.6
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 GPT-5.3-Codex and Kimi K2.6
BenchmarkGPT-5.3-CodexKimi K2.6Leader
AA Intelligence Index32.527.0GPT-5.3-Codex
Epoch Capabilities Index157.1150.9GPT-5.3-Codex
Agentic workLike-for-likePublic boards, shown as published, kept out of the index16
Agentic work benchmarks for GPT-5.3-Codex and Kimi K2.6
BenchmarkGPT-5.3-CodexKimi K2.6Leader
AA Agentic IndexNot measured20.5Only Kimi K2.6 measured
Design Arena: agents building web apps10321268Kimi K2.6
Design Arena: agents building full-stack apps9831155Kimi K2.6
Design Arena: agents building mobile apps10531156Kimi K2.6
Design Arena: agents building Android apps10841161Kimi K2.6
Design Arena: agents building Godot games11241120GPT-5.3-Codex
Design Arena: agents building gamesNot measured1141Only Kimi K2.6 measured
Design Arena: HTML slidesNot measured1135Only Kimi K2.6 measured
Design Arena: PowerPoint slidesNot measured1103Only Kimi K2.6 measured
Design Arena: spreadsheetsNot measured1276Only Kimi K2.6 measured
Finance Agent (Vals AI)Not measured44.9%Only Kimi K2.6 measured
Tax Agent Bench (Vals AI)Not measured12.4%Only Kimi K2.6 measured
Legal Research Bench (Vals AI)Not measured15.9%Only Kimi K2.6 measured
Excel Modeling Benchmark (Vals AI)Not measured57.9%Only Kimi K2.6 measured
τ²-Bench Telecom86.0%95.9%Kimi K2.6
METR time horizons74.5%Not measuredOnly GPT-5.3-Codex measured
OSWorld 2.0Not measured4.6%Only Kimi K2.6 measured
Vending-Bench 2$5,940$6,205Kimi K2.6
Neither model has a result on the other 23 boards here
ReasoningLike-for-likePublic boards, shown as published, kept out of the index20
Reasoning benchmarks for GPT-5.3-Codex and Kimi K2.6
BenchmarkGPT-5.3-CodexKimi K2.6Leader
GPQA DiamondNot measured89.1%Only Kimi K2.6 measured
MMMU Pro (Vals AI)Not measured86.3%Only Kimi K2.6 measured
GPQA Diamond (Artificial Analysis run)91.5%91.1%GPT-5.3-Codex
Humanity's Last Exam (Artificial Analysis run)42.5%37.5%GPT-5.3-Codex
GPQA Diamond (Epoch AI run)Not measured90.8%Only Kimi K2.6 measured
Chess puzzlesNot measured20.0%Only Kimi K2.6 measured
Mystery game puzzlesNot measured18.0%Only Kimi K2.6 measured
EBR-benchNot measured2.4%Only Kimi K2.6 measured
LMArena Text: hard promptsNot measured1470Only Kimi K2.6 measured
LMArena Text: expertNot measured1491Only Kimi K2.6 measured
LMArena Text: hard prompts in EnglishNot measured1471Only Kimi K2.6 measured
LMArena Vision: diagramsNot measured1298Only Kimi K2.6 measured
LMArena Vision: homeworkNot measured1310Only Kimi K2.6 measured
Neither model has a result on the other 9 boards here
MathDirectional onlyPublic boards, shown as published, kept out of the index6 boards, none shared
Math benchmarks for GPT-5.3-Codex and Kimi K2.6
BenchmarkGPT-5.3-CodexKimi K2.6Leader
OTIS Mock AIMENot measured96.1%Only Kimi K2.6 measured
FrontierMath, tiers 1 to 3Not measured57.2%Only Kimi K2.6 measured
FrontierMath, tier 4Not measured25.6%Only Kimi K2.6 measured
ProofBenchNot measured16.0%Only Kimi K2.6 measured
LMArena Text: mathNot measured1474Only Kimi K2.6 measured
LMArena Text: mathematical workNot measured1480Only Kimi K2.6 measured
Neither model has a result on the other 7 boards here
KnowledgeDirectional onlyPublic boards, shown as published, kept out of the index12 boards, none shared
Knowledge benchmarks for GPT-5.3-Codex and Kimi K2.6
BenchmarkGPT-5.3-CodexKimi K2.6Leader
MMLU ProNot measured87.6%Only Kimi K2.6 measured
LegalBench (Vals AI)Not measured84.7%Only Kimi K2.6 measured
CaseLaw (Vals AI)Not measured61.2%Only Kimi K2.6 measured
CorpFin (Vals AI)Not measured66.7%Only Kimi K2.6 measured
TaxEval (Vals AI)Not measured74.7%Only Kimi K2.6 measured
MortgageTax (Vals AI)Not measured65.8%Only Kimi K2.6 measured
MedCode (Vals AI)Not measured40.1%Only Kimi K2.6 measured
SimpleQA VerifiedNot measured34.9%Only Kimi K2.6 measured
LMArena Text: scienceNot measured1468Only Kimi K2.6 measured
LMArena Text: medicine and healthcareNot measured1457Only Kimi K2.6 measured
LMArena Text: legal and governmentNot measured1462Only Kimi K2.6 measured
LMArena Text: business and financeNot measured1445Only Kimi K2.6 measured
Neither model has a result on the other 6 boards here
Web designLike-for-likePublic boards, shown as published, kept out of the index08
Web design benchmarks for GPT-5.3-Codex and Kimi K2.6
BenchmarkGPT-5.3-CodexKimi K2.6Leader
Design Arena: websites11621268Kimi K2.6
Design Arena: UI components11341263Kimi K2.6
Design Arena: game dev11611250Kimi K2.6
Design Arena: data viz11641249Kimi K2.6
Design Arena: 3D10071267Kimi K2.6
Design Arena: all code categories11441271Kimi K2.6
Design Arena: SVG11291181Kimi K2.6
Design Arena: ASCII art11521165Kimi K2.6
Neither model has a result on the other 1 board here
GeneralLike-for-likePublic boards, shown as published, kept out of the index11
General benchmarks for GPT-5.3-Codex and Kimi K2.6
BenchmarkGPT-5.3-CodexKimi K2.6Leader
Public Benefits Bench (Vals AI)Not measured56.6%Only Kimi K2.6 measured
SAGE (Vals AI)Not measured50.2%Only Kimi K2.6 measured
MedScribe (Vals AI)Not measured78.2%Only Kimi K2.6 measured
Vals Multimodal IndexNot measured56.4%Only Kimi K2.6 measured
IFBench75.4%76.0%Kimi K2.6
Long context reasoning (AA-LCR)83.3%81.0%GPT-5.3-Codex
DTBenchNot measured90.9%Only Kimi K2.6 measured
LMCANot measured37.3%Only Kimi K2.6 measured
Furniture assemblyNot measured21.7%Only Kimi K2.6 measured
ExploitBenchNot measured18.4%Only Kimi K2.6 measured
LMArena TextNot measured1455Only Kimi K2.6 measured
LMArena Text: instruction followingNot measured1451Only Kimi K2.6 measured
LMArena Text: creative writingNot measured1434Only Kimi K2.6 measured
LMArena VisionNot measured1282Only Kimi K2.6 measured
LMArena Text: EnglishNot measured1460Only Kimi K2.6 measured
LMArena Text: non-EnglishNot measured1446Only Kimi K2.6 measured
LMArena Text: ChineseNot measured1520Only Kimi K2.6 measured
LMArena Text: GermanNot measured1451Only Kimi K2.6 measured
LMArena Text: JapaneseNot measured1443Only Kimi K2.6 measured
LMArena Text: KoreanNot measured1427Only Kimi K2.6 measured
LMArena Text: FrenchNot measured1471Only Kimi K2.6 measured
LMArena Text: SpanishNot measured1464Only Kimi K2.6 measured
LMArena Text: RussianNot measured1446Only Kimi K2.6 measured
LMArena Text: PolishNot measured1438Only Kimi K2.6 measured
LMArena Text: multi-turnNot measured1453Only Kimi K2.6 measured
LMArena Text: longer queriesNot measured1468Only Kimi K2.6 measured
LMArena Text: writing and languageNot measured1439Only Kimi K2.6 measured
LMArena Text: entertainment and mediaNot measured1428Only Kimi K2.6 measured
LMArena Vision: EnglishNot measured1287Only Kimi K2.6 measured
LMArena Vision: ChineseNot measured1346Only Kimi K2.6 measured
LMArena Vision: reading textNot measured1291Only Kimi K2.6 measured
LMArena Vision: humorNot measured1280Only Kimi K2.6 measured
LMArena Vision: creative writingNot measured1273Only Kimi K2.6 measured
LMArena DocumentNot measured1451Only Kimi K2.6 measured
Neither model has a result on the other 12 boards here
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
Image generation benchmarks for GPT-5.3-Codex and Kimi K2.6
BenchmarkGPT-5.3-CodexKimi K2.6Leader
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

GPT-5.3-Codex$0.0088Fits in one request
Kimi K2.6$0.0029Fits in one request

Kimi K2.6 costs less

Repository review

50K input + 3K output tokens

GPT-5.3-Codex$0.130Fits in one request
Kimi K2.6$0.059Fits in one request

Kimi K2.6 costs less

Agent loop

200K input + 10K output tokens

GPT-5.3-Codex$0.490Fits in one request
Kimi K2.6$0.230Fits in one request

Kimi K2.6 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 GPT-5.3-Codex and Kimi K2.6
SpecificationOpenAI GPT-5.3-CodexMoonshotAI Kimi K2.6
MakerOpenAIMoonshot AI
WeightsNo public weights listedOpen weights
ReleasedFebruary 24, 2026April 20, 2026
Context window400K262K
Input $/Mtok$1.75$0.95
Output $/Mtok$14.00$4.00
Coding index60.052.1
Independent measurements behind it33
Cost per solved task$0.59$0.35
SourceOpenRouter listingOpenRouter listing

Questions

Is GPT-5.3-Codex better than Kimi K2.6 for coding?

Pick GPT-5.3-Codex for coding: it scores 60.0 on the Vibe Coding Index against 52.1 for Kimi K2.6. Pick Kimi K2.6 for output tokens 3.5x cheaper ($4.00 vs $14.00 per million) and a lower cost per solved task ($0.35 against $0.59).

Which is cheaper, GPT-5.3-Codex or Kimi K2.6?

GPT-5.3-Codex costs $1.75 per million input tokens and $14.00 per million output tokens; Kimi K2.6 costs $0.95 and $4.00. Per solved SWE-bench Verified task, GPT-5.3-Codex costs $0.59 and Kimi K2.6 $0.35.

Which has the bigger context window, GPT-5.3-Codex or Kimi K2.6?

GPT-5.3-Codex, with 400K tokens against 262K.

How many benchmarks is the GPT-5.3-Codex vs Kimi K2.6 comparison based on?

31 benchmarks have a result for both models as of October 22, 2026. GPT-5.3-Codex's coding index rests on 3 independent benchmarks and Kimi K2.6'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/gpt-5-3-codex-vs-kimi-k2-6">LLMBenchmark.ai, GPT-5.3-Codex vs Kimi K2.6</a></p>