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GPT-5.1-Codex vs Kimi K2.7 Code

Updated October 21, 2026. 20 benchmarks have a result for both. Coding is ranked on the Vibe Coding Index; every other board is shown as published.

Replace GPT-5.1-Codex Replace Kimi K2.7 Code
GPT-5.1-CodexOpenAI
Coding
50.5
Overall
23.7
Output $/M
$10.00
4
Kimi K2.7 CodeMoonshot AI
Coding
39.1
Overall
25.8
Output $/M
$3.35
16
vs boards won of 20 shared

Decision reading

Pick GPT-5.1-Codex for coding: it scores 50.5 on the Vibe Coding Index against 39.1 for Kimi K2.7 Code.

Pick Kimi K2.7 Code when output tokens cost 3.0x less, or when a solved task costs $0.35 against $0.892.

Model AGPT-5.1-CodexOpenAI50.5/1002 independent benchmarks$0.892 per solved taskModel BKimi K2.7 CodeMoonshot AI39.1/1001 independent benchmark$0.35 per solved task
Shared results
20
GPT-5.1-Codex only
6
Kimi K2.7 Code only
31
Like-for-like categories
6 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
GPT-5.1-Codex 50.5 from 2 benchmarks, Kimi K2.7 Code 39.1 from 1 benchmark.
Widest category
Coding, 16.0 points apart on average over 6 shared benchmarks.
Widest single gap
Vibe Code Bench (Vals AI): GPT-5.1-Codex 13.1% against Kimi K2.7 Code 47.2%, 34.1 points apart on a 0 to 100 scale.
Output price
GPT-5.1-Codex $10.00 against Kimi K2.7 Code $3.35 per million output tokens, 3.0x apart.
Context window
GPT-5.1-Codex takes 400K tokens, Kimi K2.7 Code 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-5.1-CodexBarsKimi K2.7 CodeTies
Coding24
Intelligence01
Agentic work13
Reasoning02
Web design05
General11
All shared boards416
CodingLike-for-likeFour of these boards feed the Vibe Coding Index24
Coding benchmarks for GPT-5.1-Codex and Kimi K2.7 Code
BenchmarkGPT-5.1-CodexKimi K2.7 CodeLeader
SWE-bench Verified66.0%Not measuredOnly GPT-5.1-Codex measured
LMArena WebDev13371474Kimi K2.7 Code
AA Coding IndexNot measured60.8Only Kimi K2.7 Code measured
LiveCodeBench (Vals AI)85.5%82.0%GPT-5.1-Codex
SWE-bench Verified (Vals AI)Not measured78.2%Only Kimi K2.7 Code measured
Vibe Code Bench (Vals AI)13.1%47.2%Kimi K2.7 Code
Code migration (Vals AI)Not measured25.4%Only Kimi K2.7 Code measured
ProgramBench (Vals AI)Not measured0.0%Only Kimi K2.7 Code measured
Terminal-Bench 2.1 (Vals AI)Not measured67.0%Only Kimi K2.7 Code measured
SkillsBench (Vals AI)Not measured50.0%Only Kimi K2.7 Code measured
LiveCodeBench (Artificial Analysis run)84.9%Not measuredOnly GPT-5.1-Codex measured
SciCodeNot measured47.8%Only Kimi K2.7 Code measured
Terminal-Bench Hard (Artificial Analysis run)34.8%44.7%Kimi K2.7 Code
Terminal-Bench57.8%Not measuredOnly GPT-5.1-Codex measured
FrontierCodeNot measured30.1%Only Kimi K2.7 Code measured
WeirdMLNot measured54.1%Only Kimi K2.7 Code measured
ALE-Bench1244.9886.2GPT-5.1-Codex
LMArena WebDev: ReactNot measured1475Only Kimi K2.7 Code measured
LMArena WebDev: HTML13461451Kimi K2.7 Code
LMArena WebDev: from an imageNot measured1513Only Kimi K2.7 Code measured
Neither model has a result on the other 18 boards here
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index01
Intelligence benchmarks for GPT-5.1-Codex and Kimi K2.7 Code
BenchmarkGPT-5.1-CodexKimi K2.7 CodeLeader
AA Intelligence Index23.725.8Kimi K2.7 Code
Epoch Capabilities IndexNot measured150.1Only Kimi K2.7 Code measured
Agentic workLike-for-likePublic boards, shown as published, kept out of the index13
Agentic work benchmarks for GPT-5.1-Codex and Kimi K2.7 Code
BenchmarkGPT-5.1-CodexKimi K2.7 CodeLeader
AA Agentic IndexNot measured21.0Only Kimi K2.7 Code measured
Design Arena: agents building web apps10181176Kimi K2.7 Code
Design Arena: agents building full-stack apps10861175Kimi K2.7 Code
Design Arena: agents building mobile apps11911143GPT-5.1-Codex
Design Arena: agents building Android appsNot measured1143Only Kimi K2.7 Code measured
Design Arena: agents building Godot gamesNot measured1147Only Kimi K2.7 Code measured
Design Arena: agents building gamesNot measured1130Only Kimi K2.7 Code measured
Design Arena: HTML slidesNot measured1201Only Kimi K2.7 Code measured
Design Arena: PowerPoint slidesNot measured1154Only Kimi K2.7 Code measured
τ²-Bench Telecom83.0%90.1%Kimi K2.7 Code
APEX-AgentsNot measured37.6%Only Kimi K2.7 Code measured
Vending-Bench 2Not measured$5,083Only Kimi K2.7 Code measured
Neither model has a result on the other 27 boards here
ReasoningLike-for-likePublic boards, shown as published, kept out of the index02
Reasoning benchmarks for GPT-5.1-Codex and Kimi K2.7 Code
BenchmarkGPT-5.1-CodexKimi K2.7 CodeLeader
GPQA Diamond (Artificial Analysis run)86.0%89.6%Kimi K2.7 Code
Humanity's Last Exam (Artificial Analysis run)25.7%35.0%Kimi K2.7 Code
GPQA Diamond (Epoch AI run)Not measured87.9%Only Kimi K2.7 Code measured
SimpleBenchNot measured57.9%Only Kimi K2.7 Code measured
Chess puzzlesNot measured14.0%Only Kimi K2.7 Code measured
Neither model has a result on the other 16 boards here
MathDirectional onlyPublic boards, shown as published, kept out of the index5 boards, none shared
Math benchmarks for GPT-5.1-Codex and Kimi K2.7 Code
BenchmarkGPT-5.1-CodexKimi K2.7 CodeLeader
AA Math Index95.7Not measuredOnly GPT-5.1-Codex measured
AIME 2025 (Artificial Analysis run)95.7%Not measuredOnly GPT-5.1-Codex measured
OTIS Mock AIMENot measured95.6%Only Kimi K2.7 Code measured
FrontierMath, tiers 1 to 3Not measured54.0%Only Kimi K2.7 Code measured
FrontierMath, tier 4Not measured12.2%Only Kimi K2.7 Code measured
Neither model has a result on the other 8 boards here
KnowledgeDirectional onlyPublic boards, shown as published, kept out of the index2 boards, none shared
Knowledge benchmarks for GPT-5.1-Codex and Kimi K2.7 Code
BenchmarkGPT-5.1-CodexKimi K2.7 CodeLeader
MMLU Pro (Artificial Analysis run)86.0%Not measuredOnly GPT-5.1-Codex measured
SimpleQA VerifiedNot measured36.5%Only Kimi K2.7 Code measured
Neither model has a result on the other 15 boards here
Web designLike-for-likePublic boards, shown as published, kept out of the index05
Web design benchmarks for GPT-5.1-Codex and Kimi K2.7 Code
BenchmarkGPT-5.1-CodexKimi K2.7 CodeLeader
Design Arena: websites11621264Kimi K2.7 Code
Design Arena: UI components12371259Kimi K2.7 Code
Design Arena: game dev11381220Kimi K2.7 Code
Design Arena: data viz12131226Kimi K2.7 Code
Design Arena: 3DNot measured1241Only Kimi K2.7 Code measured
Design Arena: all code categories11531253Kimi K2.7 Code
Design Arena: SVGNot measured1176Only Kimi K2.7 Code measured
Design Arena: ASCII artNot measured1196Only Kimi K2.7 Code measured
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-5.1-Codex and Kimi K2.7 Code
BenchmarkGPT-5.1-CodexKimi K2.7 CodeLeader
IFBench70.0%63.1%GPT-5.1-Codex
Long context reasoning (AA-LCR)69.3%79.3%Kimi K2.7 Code
Surface Evolver BenchNot measured48.8%Only Kimi K2.7 Code measured
Neither model has a result on the other 43 boards here
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
Image generation benchmarks for GPT-5.1-Codex and Kimi K2.7 Code
BenchmarkGPT-5.1-CodexKimi K2.7 CodeLeader
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-5.1-Codex$0.0063Fits in one request
Kimi K2.7 Code$0.0023Fits in one request

Kimi K2.7 Code costs less

Repository review

50K input + 3K output tokens

GPT-5.1-Codex$0.092Fits in one request
Kimi K2.7 Code$0.044Fits in one request

Kimi K2.7 Code costs less

Agent loop

200K input + 10K output tokens

GPT-5.1-Codex$0.350Fits in one request
Kimi K2.7 Code$0.168Fits in one request

Kimi K2.7 Code 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-5.1-Codex and Kimi K2.7 Code
SpecificationOpenAI GPT-5.1-CodexMoonshotAI Kimi K2.7 Code
MakerOpenAIMoonshot AI
WeightsNo public weights listedOpen weights
ReleasedNovember 13, 2025June 12, 2026
Context window400K262K
Input $/Mtok$1.25$0.6712
Output $/Mtok$10.00$3.35
Coding index50.539.1
Independent measurements behind it21
Cost per solved task$0.892$0.35
SourceOpenRouter listingOpenRouter listing

Questions

Is GPT-5.1-Codex better than Kimi K2.7 Code for coding?

Pick GPT-5.1-Codex for coding: it scores 50.5 on the Vibe Coding Index against 39.1 for Kimi K2.7 Code. Pick Kimi K2.7 Code when output tokens cost 3.0x less, or when a solved task costs $0.35 against $0.892.

Which is cheaper, GPT-5.1-Codex or Kimi K2.7 Code?

GPT-5.1-Codex costs $1.25 per million input tokens and $10.00 per million output tokens; Kimi K2.7 Code costs $0.6712 and $3.35. Per solved SWE-bench Verified task, GPT-5.1-Codex costs $0.892 and Kimi K2.7 Code $0.35.

Which has the bigger context window, GPT-5.1-Codex or Kimi K2.7 Code?

GPT-5.1-Codex, with 400K tokens against 262K.

How many benchmarks is the GPT-5.1-Codex vs Kimi K2.7 Code comparison based on?

20 benchmarks have a result for both models as of October 21, 2026. GPT-5.1-Codex's coding index rests on 2 independent benchmarks and Kimi K2.7 Code's on 1. Where only one model has a result, the page says so instead of naming a winner.

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