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GPT-5.1-Codex vs Grok 4.3

Grok 4.3 leads GPT-5.1-Codex on coding, 37.4 to 15.3 on the Vibe Coding Index, and Grok 4.3 costs 4.0x less per output token ($2.50 vs $10.00 per million). Updated October 22, 2026; 20 benchmarks have a result for both.

Replace GPT-5.1-Codex Replace Grok 4.3
GPT-5.1-CodexOpenAI
Coding
15.3
Overall
No data
Output $/M
$10.00
6
Grok 4.3xAI
Coding
37.4
Overall
53.1
Output $/M
$2.50
14
vs boards won of 20 shared

GPT-5.1-Codex or Grok 4.3: which to pick

Pick Grok 4.3 for coding: it scores 37.4 on the Vibe Coding Index against 15.3 for GPT-5.1-Codex.

Pick GPT-5.1-Codex for work measured by LiveCodeBench (Vals AI) or ALE-Bench, where it leads.

Model AGPT-5.1-CodexOpenAI15.3/1002 independent benchmarks$0.892 per solved taskModel BGrok 4.3xAI37.4/1003 independent benchmarks$0.31 per solved task
Shared results
20
GPT-5.1-Codex only
6
Grok 4.3 only
85
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-5.1-Codex 15.3 from 2 benchmarks, Grok 4.3 37.4 from 3 benchmarks.
Widest category
Agentic work, 13.7 points apart on average over 4 shared benchmarks.
Widest single gap
Design Arena: agents building mobile apps: GPT-5.1-Codex 1191 against Grok 4.3 1058, 16.6 points apart on a 0 to 100 scale.
Output price
GPT-5.1-Codex $10.00 against Grok 4.3 $2.50 per million output tokens, 4.0x apart.
Context window
GPT-5.1-Codex takes 400K tokens, Grok 4.3 1M.

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-CodexBarsGrok 4.3Ties
Coding24
Intelligence01
Agentic work22
Reasoning02
Web design23
General02
All shared boards614
CodingLike-for-likeSix of these boards feed the Vibe Coding Index24
Coding benchmarks for GPT-5.1-Codex and Grok 4.3
BenchmarkGPT-5.1-CodexGrok 4.3Leader
SWE-bench Verified66.0%Not measuredOnly GPT-5.1-Codex measured
LMArena WebDev13371358Grok 4.3
AA Coding IndexNot measured42.2Only Grok 4.3 measured
LiveCodeBench (Vals AI)85.5%84.5%GPT-5.1-Codex
SWE-bench Verified (Vals AI)Not measured71.4%Only Grok 4.3 measured
Vibe Code Bench (Vals AI)13.1%19.4%Grok 4.3
Code migration (Vals AI)Not measured6.8%Only Grok 4.3 measured
ProgramBench (Vals AI)Not measured0.0%Only Grok 4.3 measured
Terminal-Bench 2.1 (Vals AI)Not measured42.0%Only Grok 4.3 measured
SkillsBench (Vals AI)Not measured40.6%Only Grok 4.3 measured
LiveCodeBench (Artificial Analysis run)84.9%Not measuredOnly GPT-5.1-Codex measured
SciCodeNot measured48.3%Only Grok 4.3 measured
Terminal-Bench Hard (Artificial Analysis run)34.8%37.9%Grok 4.3
Terminal-Bench57.8%Not measuredOnly GPT-5.1-Codex measured
WeirdMLNot measured49.9%Only Grok 4.3 measured
ALE-Bench1244.9944.2GPT-5.1-Codex
LMArena Text: codingNot measured1415Only Grok 4.3 measured
LMArena Text: software and ITNot measured1416Only Grok 4.3 measured
LMArena WebDev: ReactNot measured1353Only Grok 4.3 measured
LMArena WebDev: HTML13461367Grok 4.3
LMArena WebDev: from an imageNot measured1375Only Grok 4.3 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 Grok 4.3
BenchmarkGPT-5.1-CodexGrok 4.3Leader
AA Intelligence Index23.724.9Grok 4.3
Neither model has a result on the other 1 board here
Agentic workLike-for-likePublic boards, shown as published, kept out of the index22
Agentic work benchmarks for GPT-5.1-Codex and Grok 4.3
BenchmarkGPT-5.1-CodexGrok 4.3Leader
AA Agentic IndexNot measured15.5Only Grok 4.3 measured
Design Arena: agents building web apps10181126Grok 4.3
Design Arena: agents building full-stack apps10861006GPT-5.1-Codex
Design Arena: agents building mobile apps11911058GPT-5.1-Codex
Design Arena: agents building Android appsNot measured962Only Grok 4.3 measured
Design Arena: agents building Godot gamesNot measured914Only Grok 4.3 measured
Design Arena: agents building gamesNot measured1007Only Grok 4.3 measured
Design Arena: HTML slidesNot measured959Only Grok 4.3 measured
Design Arena: PowerPoint slidesNot measured988Only Grok 4.3 measured
Design Arena: spreadsheetsNot measured879Only Grok 4.3 measured
Finance Agent (Vals AI)Not measured37.7%Only Grok 4.3 measured
Tax Agent Bench (Vals AI)Not measured6.2%Only Grok 4.3 measured
Legal Research Bench (Vals AI)Not measured15.4%Only Grok 4.3 measured
Excel Modeling Benchmark (Vals AI)Not measured18.4%Only Grok 4.3 measured
τ²-Bench Telecom83.0%97.7%Grok 4.3
Vending-Bench 2Not measured$35Only Grok 4.3 measured
LMArena SearchNot measured1166Only Grok 4.3 measured
Neither model has a result on the other 24 boards here
ReasoningLike-for-likePublic boards, shown as published, kept out of the index02
Reasoning benchmarks for GPT-5.1-Codex and Grok 4.3
BenchmarkGPT-5.1-CodexGrok 4.3Leader
GPQA DiamondNot measured91.4%Only Grok 4.3 measured
MMMU Pro (Vals AI)Not measured83.1%Only Grok 4.3 measured
GPQA Diamond (Artificial Analysis run)86.0%90.1%Grok 4.3
Humanity's Last Exam (Artificial Analysis run)25.7%37.2%Grok 4.3
GPQA Diamond (Epoch AI run)Not measured88.8%Only Grok 4.3 measured
Chess puzzlesNot measured18.0%Only Grok 4.3 measured
LMArena Text: hard promptsNot measured1396Only Grok 4.3 measured
LMArena Text: expertNot measured1384Only Grok 4.3 measured
LMArena Text: hard prompts in EnglishNot measured1402Only Grok 4.3 measured
LMArena Vision: diagramsNot measured1241Only Grok 4.3 measured
LMArena Vision: homeworkNot measured1241Only Grok 4.3 measured
Neither model has a result on the other 11 boards here
MathDirectional onlyPublic boards, shown as published, kept out of the index8 boards, none shared
Math benchmarks for GPT-5.1-Codex and Grok 4.3
BenchmarkGPT-5.1-CodexGrok 4.3Leader
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 measured93.3%Only Grok 4.3 measured
FrontierMath, tiers 1 to 3Not measured42.8%Only Grok 4.3 measured
FrontierMath, tier 4Not measured14.6%Only Grok 4.3 measured
ProofBenchNot measured11.0%Only Grok 4.3 measured
LMArena Text: mathNot measured1387Only Grok 4.3 measured
LMArena Text: mathematical workNot measured1396Only Grok 4.3 measured
Neither model has a result on the other 5 boards here
KnowledgeDirectional onlyPublic boards, shown as published, kept out of the index13 boards, none shared
Knowledge benchmarks for GPT-5.1-Codex and Grok 4.3
BenchmarkGPT-5.1-CodexGrok 4.3Leader
MMLU ProNot measured85.8%Only Grok 4.3 measured
LegalBench (Vals AI)Not measured84.5%Only Grok 4.3 measured
CaseLaw (Vals AI)Not measured79.3%Only Grok 4.3 measured
CorpFin (Vals AI)Not measured68.5%Only Grok 4.3 measured
TaxEval (Vals AI)Not measured70.8%Only Grok 4.3 measured
MortgageTax (Vals AI)Not measured48.3%Only Grok 4.3 measured
MedCode (Vals AI)Not measured38.1%Only Grok 4.3 measured
MMLU Pro (Artificial Analysis run)86.0%Not measuredOnly GPT-5.1-Codex measured
SimpleQA VerifiedNot measured33.2%Only Grok 4.3 measured
LMArena Text: scienceNot measured1399Only Grok 4.3 measured
LMArena Text: medicine and healthcareNot measured1384Only Grok 4.3 measured
LMArena Text: legal and governmentNot measured1386Only Grok 4.3 measured
LMArena Text: business and financeNot measured1381Only Grok 4.3 measured
Neither model has a result on the other 5 boards here
Web designLike-for-likePublic boards, shown as published, kept out of the index23
Web design benchmarks for GPT-5.1-Codex and Grok 4.3
BenchmarkGPT-5.1-CodexGrok 4.3Leader
Design Arena: websites11611196Grok 4.3
Design Arena: UI components12341190GPT-5.1-Codex
Design Arena: game dev11371173Grok 4.3
Design Arena: data viz12131179GPT-5.1-Codex
Design Arena: 3DNot measured1124Only Grok 4.3 measured
Design Arena: all code categories11521186Grok 4.3
Design Arena: SVGNot measured1080Only Grok 4.3 measured
Design Arena: ASCII artNot measured1125Only Grok 4.3 measured
Neither model has a result on the other 1 board here
GeneralLike-for-likePublic boards, shown as published, kept out of the index02
General benchmarks for GPT-5.1-Codex and Grok 4.3
BenchmarkGPT-5.1-CodexGrok 4.3Leader
Public Benefits Bench (Vals AI)Not measured51.7%Only Grok 4.3 measured
SAGE (Vals AI)Not measured19.7%Only Grok 4.3 measured
MedScribe (Vals AI)Not measured74.4%Only Grok 4.3 measured
Vals Multimodal IndexNot measured43.3%Only Grok 4.3 measured
IFBench70.0%83.3%Grok 4.3
Long context reasoning (AA-LCR)69.3%75.0%Grok 4.3
DTBenchNot measured90.7%Only Grok 4.3 measured
LMCANot measured38.3%Only Grok 4.3 measured
LMArena TextNot measured1397Only Grok 4.3 measured
LMArena Text: instruction followingNot measured1366Only Grok 4.3 measured
LMArena Text: creative writingNot measured1380Only Grok 4.3 measured
LMArena VisionNot measured1229Only Grok 4.3 measured
LMArena Text: EnglishNot measured1404Only Grok 4.3 measured
LMArena Text: non-EnglishNot measured1385Only Grok 4.3 measured
LMArena Text: ChineseNot measured1422Only Grok 4.3 measured
LMArena Text: GermanNot measured1395Only Grok 4.3 measured
LMArena Text: JapaneseNot measured1379Only Grok 4.3 measured
LMArena Text: KoreanNot measured1354Only Grok 4.3 measured
LMArena Text: FrenchNot measured1411Only Grok 4.3 measured
LMArena Text: SpanishNot measured1399Only Grok 4.3 measured
LMArena Text: RussianNot measured1399Only Grok 4.3 measured
LMArena Text: PolishNot measured1398Only Grok 4.3 measured
LMArena Text: multi-turnNot measured1406Only Grok 4.3 measured
LMArena Text: longer queriesNot measured1393Only Grok 4.3 measured
LMArena Text: writing and languageNot measured1385Only Grok 4.3 measured
LMArena Text: entertainment and mediaNot measured1370Only Grok 4.3 measured
LMArena Vision: EnglishNot measured1235Only Grok 4.3 measured
LMArena Vision: ChineseNot measured1257Only Grok 4.3 measured
LMArena Vision: reading textNot measured1235Only Grok 4.3 measured
LMArena Vision: humorNot measured1222Only Grok 4.3 measured
LMArena Vision: recognizing thingsNot measured1217Only Grok 4.3 measured
LMArena Vision: creative writingNot measured1237Only Grok 4.3 measured
Neither model has a result on the other 14 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 Grok 4.3
BenchmarkGPT-5.1-CodexGrok 4.3Leader
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
Grok 4.3$0.0025Fits in one request

Grok 4.3 costs less

Repository review

50K input + 3K output tokens

GPT-5.1-Codex$0.092Fits in one request
Grok 4.3$0.070Fits in one request

Grok 4.3 costs less

Agent loop

200K input + 10K output tokens

GPT-5.1-Codex$0.350Fits in one request
Grok 4.3$0.275Fits in one request

Grok 4.3 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 Grok 4.3
SpecificationOpenAI GPT-5.1-CodexSpaceXAI Grok 4.3
MakerOpenAIxAI
WeightsNo public weights listedNo public weights listed
ReleasedNovember 13, 2025April 30, 2026
Context window400K1M
Input $/Mtok$1.25$1.25
Output $/Mtok$10.00$2.50
Coding index15.337.4
Independent measurements behind it23
Cost per solved task$0.892$0.31
SourceOpenRouter listingOpenRouter listing

Questions

Is GPT-5.1-Codex better than Grok 4.3 for coding?

Pick Grok 4.3 for coding: it scores 37.4 on the Vibe Coding Index against 15.3 for GPT-5.1-Codex. Pick GPT-5.1-Codex for work measured by LiveCodeBench (Vals AI) or ALE-Bench, where it leads.

Which is cheaper, GPT-5.1-Codex or Grok 4.3?

GPT-5.1-Codex costs $1.25 per million input tokens and $10.00 per million output tokens; Grok 4.3 costs $1.25 and $2.50. Per solved SWE-bench Verified task, GPT-5.1-Codex costs $0.892 and Grok 4.3 $0.31.

Which has the bigger context window, GPT-5.1-Codex or Grok 4.3?

Grok 4.3, with 1M tokens against 400K.

How many benchmarks is the GPT-5.1-Codex vs Grok 4.3 comparison based on?

20 benchmarks have a result for both models as of October 22, 2026. GPT-5.1-Codex's coding index rests on 2 independent benchmarks and Grok 4.3's on 3. Where only one model has a result, the page says so instead of naming a winner.

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<iframe src="https://llmbenchmark.ai/embed/compare/gpt-5-1-codex-vs-grok-4-3" title="GPT-5.1-Codex vs Grok 4.3, LLMBenchmark.ai" width="100%" height="360" style="border:0;max-width:100%" loading="lazy"></iframe>
<p style="font:13px/1.4 sans-serif;margin:6px 0 0">Source: <a href="https://llmbenchmark.ai/compare/gpt-5-1-codex-vs-grok-4-3">LLMBenchmark.ai, GPT-5.1-Codex vs Grok 4.3</a></p>