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GPT-5.1 vs Grok 4.5

Grok 4.5 leads GPT-5.1 on coding, 58.6 to 40.4 on the Vibe Coding Index, and Grok 4.5 costs 1.7x less per output token ($6.00 vs $10.00 per million). Updated October 22, 2026; 80 benchmarks have a result for both.

Replace GPT-5.1 Replace Grok 4.5
GPT-5.1OpenAI
Coding
40.4
Overall
55.0
Output $/M
$10.00
13
Grok 4.5xAI
Coding
58.6
Overall
62.1
Output $/M
$6.00
67
vs boards won of 80 shared

GPT-5.1 or Grok 4.5: which to pick

Pick Grok 4.5 for coding: it scores 58.6 on the Vibe Coding Index against 40.4 for GPT-5.1.

Pick GPT-5.1 for work measured by WeirdML or MMMU Pro (Vals AI), where it leads.

Model AGPT-5.1OpenAI40.4/1003 independent benchmarks$1.02 per solved taskModel BGrok 4.5xAI58.6/1006 independent benchmarks$0.62 per solved task
Shared results
80
GPT-5.1 only
21
Grok 4.5 only
43
Like-for-like categories
8 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 40.4 from 3 benchmarks, Grok 4.5 58.6 from 6 benchmarks.
Widest category
Coding, 20.0 points apart on average over 11 shared benchmarks.
Widest single gap
Vibe Code Bench (Vals AI): GPT-5.1 24.6% against Grok 4.5 69.0%, 44.4 points apart on a 0 to 100 scale.
Output price
GPT-5.1 $10.00 against Grok 4.5 $6.00 per million output tokens, 1.7x apart.
Context window
GPT-5.1 takes 400K tokens, Grok 4.5 500K.

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-5.1BarsGrok 4.5Ties
Coding110
Intelligence02
Agentic work01
Reasoning311
Math03
Knowledge39
Web design08
General623
All shared boards1367
CodingLike-for-likeSix of these boards feed the Vibe Coding Index110
Coding benchmarks for GPT-5.1 and Grok 4.5
BenchmarkGPT-5.1Grok 4.5Leader
SWE-bench Verified66.0%Not measuredOnly GPT-5.1 measured
LiveBench codingNot measured94.3%Only Grok 4.5 measured
LMArena WebDev13961553Grok 4.5
AA Coding Index49.472.4Grok 4.5
LiveCodeBench (Vals AI)86.5%87.3%Grok 4.5
SWE-bench Verified (Vals AI)69.8%86.6%Grok 4.5
Terminal-Bench 4 (Vals AI)Not measured8.6%Only Grok 4.5 measured
Vibe Code Bench (Vals AI)24.6%69.0%Grok 4.5
Code migration (Vals AI)Not measured36.6%Only Grok 4.5 measured
ProgramBench (Vals AI)Not measured0.0%Only Grok 4.5 measured
IOI (Vals AI)Not measured40.6%Only Grok 4.5 measured
Terminal-Bench 2.1 (Vals AI)Not measured67.8%Only Grok 4.5 measured
SkillsBench (Vals AI)Not measured66.0%Only Grok 4.5 measured
CyberBench (Vals AI)Not measured71.0%Only Grok 4.5 measured
LiveCodeBench (Artificial Analysis run)86.8%Not measuredOnly GPT-5.1 measured
SciCodeNot measured55.0%Only Grok 4.5 measured
Terminal-Bench Hard (Artificial Analysis run)45.5%Not measuredOnly GPT-5.1 measured
Terminal-Bench47.6%Not measuredOnly GPT-5.1 measured
FrontierCodeNot measured42.4%Only Grok 4.5 measured
GSO-Bench13.7%Not measuredOnly GPT-5.1 measured
WeirdML60.8%46.4%GPT-5.1
ALE-BenchNot measured1309.3Only Grok 4.5 measured
LMArena Text: coding14531474Grok 4.5
LMArena Text: software and IT14541471Grok 4.5
LMArena WebDev: React13071556Grok 4.5
LMArena WebDev: HTML14051567Grok 4.5
LMArena WebDev: from an image14211562Grok 4.5
SciCodeNot measured6.5%Only Grok 4.5 measured
Neither model has a result on the other 11 boards here
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index02
Intelligence benchmarks for GPT-5.1 and Grok 4.5
BenchmarkGPT-5.1Grok 4.5Leader
AA Intelligence Index24.738.8Grok 4.5
Epoch Capabilities Index149.8154.1Grok 4.5
Agentic workLike-for-likePublic boards, shown as published, kept out of the index01
Agentic work benchmarks for GPT-5.1 and Grok 4.5
BenchmarkGPT-5.1Grok 4.5Leader
AA Agentic IndexNot measured41.2Only Grok 4.5 measured
Design Arena: agents building web appsNot measured1218Only Grok 4.5 measured
Design Arena: agents building full-stack appsNot measured1249Only Grok 4.5 measured
Design Arena: agents building mobile appsNot measured1220Only Grok 4.5 measured
Design Arena: agents building Android appsNot measured1236Only Grok 4.5 measured
Design Arena: agents building Godot gamesNot measured1229Only Grok 4.5 measured
Design Arena: agents building gamesNot measured1236Only Grok 4.5 measured
Design Arena: HTML slidesNot measured1205Only Grok 4.5 measured
Design Arena: PowerPoint slidesNot measured1230Only Grok 4.5 measured
LiveBench researchNot measured85.9%Only Grok 4.5 measured
LiveBench browserNot measured44.0%Only Grok 4.5 measured
LiveBench long agenticNot measured27.9%Only Grok 4.5 measured
SREBench (Vals AI)Not measured0.8%Only Grok 4.5 measured
Finance Agent (Vals AI)Not measured48.4%Only Grok 4.5 measured
Tax Agent Bench (Vals AI)Not measured24.9%Only Grok 4.5 measured
Legal Research Bench (Vals AI)Not measured38.0%Only Grok 4.5 measured
Excel Modeling Benchmark (Vals AI)Not measured52.9%Only Grok 4.5 measured
Time Horizon Index (Vals AI)Not measured6.3%Only Grok 4.5 measured
τ²-Bench Telecom81.9%Not measuredOnly GPT-5.1 measured
APEX-AgentsNot measured56.2%Only Grok 4.5 measured
DeepResearch Bench42.8%Not measuredOnly GPT-5.1 measured
PostTrainBenchNot measured23.4%Only Grok 4.5 measured
Vending-Bench 2$1,473$3,887Grok 4.5
LMArena SearchNot measured1216Only Grok 4.5 measured
Neither model has a result on the other 17 boards here
ReasoningLike-for-likePublic boards, shown as published, kept out of the index311
Reasoning benchmarks for GPT-5.1 and Grok 4.5
BenchmarkGPT-5.1Grok 4.5Leader
GPQA Diamond86.6%92.9%Grok 4.5
LiveBench reasoningNot measured87.2%Only Grok 4.5 measured
MMMU Pro (Vals AI)83.2%61.8%GPT-5.1
GPQA Diamond (Artificial Analysis run)87.3%93.1%Grok 4.5
Humanity's Last Exam (Artificial Analysis run)28.5%42.7%Grok 4.5
GPQA Diamond (Epoch AI run)87.6%93.4%Grok 4.5
ARC-AGI72.8%87.2%Grok 4.5
ARC-AGI-217.6%52.6%Grok 4.5
SimpleBench53.2%70.0%Grok 4.5
Chess puzzles42.0%35.0%GPT-5.1
Mystery game puzzles19.0%Not measuredOnly GPT-5.1 measured
VPCT58.7%Not measuredOnly GPT-5.1 measured
LMArena Text: hard prompts14571462Grok 4.5
LMArena Text: expert14701465GPT-5.1
LMArena Text: hard prompts in English14621464Grok 4.5
LMArena Vision: diagrams12641304Grok 4.5
LMArena Vision: homework12721295Grok 4.5
Kagi LLM BenchmarkNot measured83.5%Only Grok 4.5 measured
Neither model has a result on the other 4 boards here
MathLike-for-likePublic boards, shown as published, kept out of the index03
Math benchmarks for GPT-5.1 and Grok 4.5
BenchmarkGPT-5.1Grok 4.5Leader
AIME93.3%Not measuredOnly GPT-5.1 measured
MGSM (Vals AI)93.0%Not measuredOnly GPT-5.1 measured
AA Math Index94.0Not measuredOnly GPT-5.1 measured
AIME 2025 (Artificial Analysis run)94.0%Not measuredOnly GPT-5.1 measured
OTIS Mock AIME88.6%97.8%Grok 4.5
FrontierMath, tiers 1 to 3Not measured57.2%Only Grok 4.5 measured
FrontierMath, tier 4Not measured24.4%Only Grok 4.5 measured
ProofBenchNot measured31.0%Only Grok 4.5 measured
LMArena Text: math14461460Grok 4.5
LMArena Text: mathematical work14491482Grok 4.5
Neither model has a result on the other 3 boards here
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index39
Knowledge benchmarks for GPT-5.1 and Grok 4.5
BenchmarkGPT-5.1Grok 4.5Leader
MMLU Pro86.4%89.2%Grok 4.5
LegalBench (Vals AI)85.7%86.0%Grok 4.5
CaseLaw (Vals AI)73.4%Not measuredOnly GPT-5.1 measured
CorpFin (Vals AI)63.8%67.4%Grok 4.5
TaxEval (Vals AI)74.9%71.7%GPT-5.1
MortgageTax (Vals AI)61.4%61.8%Grok 4.5
MedQA (Vals AI)96.4%Not measuredOnly GPT-5.1 measured
MedCode (Vals AI)52.7%43.3%GPT-5.1
MMLU Pro (Artificial Analysis run)87.0%Not measuredOnly GPT-5.1 measured
SimpleQA Verified48.0%48.3%Grok 4.5
LMArena Text: science14591464Grok 4.5
LMArena Text: medicine and healthcare14561440GPT-5.1
LMArena Text: legal and government14591463Grok 4.5
LMArena Text: business and finance14311441Grok 4.5
FACTS Benchmark Suite45.0%50.2%Grok 4.5
Neither model has a result on the other 3 boards here
Web designLike-for-likePublic boards, shown as published, kept out of the index08
Web design benchmarks for GPT-5.1 and Grok 4.5
BenchmarkGPT-5.1Grok 4.5Leader
Design Arena: websites11871281Grok 4.5
Design Arena: UI components11631280Grok 4.5
Design Arena: game dev11781264Grok 4.5
Design Arena: data viz12041266Grok 4.5
Design Arena: 3D10601257Grok 4.5
Design Arena: all code categories11701275Grok 4.5
Design Arena: SVG11491215Grok 4.5
Design Arena: ASCII art11191256Grok 4.5
LiveBench designNot measured78.1%Only Grok 4.5 measured
GeneralLike-for-likePublic boards, shown as published, kept out of the index623
General benchmarks for GPT-5.1 and Grok 4.5
BenchmarkGPT-5.1Grok 4.5Leader
LiveBench data analysisNot measured73.0%Only Grok 4.5 measured
SAGE (Vals AI)43.2%35.0%GPT-5.1
MedScribe (Vals AI)88.1%86.9%GPT-5.1
Vals Multimodal IndexNot measured63.4%Only Grok 4.5 measured
IFBench72.9%Not measuredOnly GPT-5.1 measured
Long context reasoning (AA-LCR)80.0%79.3%GPT-5.1
DTBench90.1%96.5%Grok 4.5
LMCA43.9%45.2%Grok 4.5
CL-bench23.7%Not measuredOnly GPT-5.1 measured
Surface Evolver BenchNot measured74.4%Only Grok 4.5 measured
Furniture assemblyNot measured22.5%Only Grok 4.5 measured
CL-bench Life17.3%Not measuredOnly GPT-5.1 measured
LMArena Text14431448Grok 4.5
LMArena Text: instruction following14431445Grok 4.5
LMArena Text: creative writing14271442Grok 4.5
LMArena Vision12501287Grok 4.5
LMArena Text: English14511453Grok 4.5
LMArena Text: non-English14311440Grok 4.5
LMArena Text: Chinese14951495GPT-5.1
LMArena Text: German14381448Grok 4.5
LMArena Text: Japanese14531430GPT-5.1
LMArena Text: Korean14011406Grok 4.5
LMArena Text: French14501457Grok 4.5
LMArena Text: Spanish14331451Grok 4.5
LMArena Text: Russian14351449Grok 4.5
LMArena Text: Polish14401432GPT-5.1
LMArena Text: multi-turn14501456Grok 4.5
LMArena Text: longer queries14481462Grok 4.5
LMArena Text: writing and language14281445Grok 4.5
LMArena Text: entertainment and media14151434Grok 4.5
LMArena Vision: English12521285Grok 4.5
LMArena Vision: Chinese12701345Grok 4.5
LMArena Vision: reading text12551293Grok 4.5
LMArena Vision: humor12631276Grok 4.5
LMArena Vision: captioning1252Not measuredOnly GPT-5.1 measured
LMArena Vision: recognizing things1232Not measuredOnly GPT-5.1 measured
LMArena Vision: creative writing12661293Grok 4.5
LMArena Document14031452Grok 4.5
Neither model has a result on the other 8 boards here
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
Image generation benchmarks for GPT-5.1 and Grok 4.5
BenchmarkGPT-5.1Grok 4.5Leader
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$0.0063Fits in one request
Grok 4.5$0.0050Fits in one request

Grok 4.5 costs less

Repository review

50K input + 3K output tokens

GPT-5.1$0.092Fits in one request
Grok 4.5$0.118Fits in one request

GPT-5.1 costs less

Agent loop

200K input + 10K output tokens

GPT-5.1$0.350Fits in one request
Grok 4.5$0.460Fits in one request

GPT-5.1 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 and Grok 4.5
SpecificationOpenAI GPT-5.1SpaceXAI Grok 4.5
MakerOpenAIxAI
WeightsNo public weights listedNo public weights listed
ReleasedNovember 13, 2025July 8, 2026
Context window400K500K
Input $/Mtok$1.25$2.00
Output $/Mtok$10.00$6.00
Coding index40.458.6
Independent measurements behind it36
Cost per solved task$1.02$0.62
SourceOpenRouter listingOpenRouter listing

Questions

Is GPT-5.1 better than Grok 4.5 for coding?

Pick Grok 4.5 for coding: it scores 58.6 on the Vibe Coding Index against 40.4 for GPT-5.1. Pick GPT-5.1 for work measured by WeirdML or MMMU Pro (Vals AI), where it leads.

Which is cheaper, GPT-5.1 or Grok 4.5?

GPT-5.1 costs $1.25 per million input tokens and $10.00 per million output tokens; Grok 4.5 costs $2.00 and $6.00. Per solved SWE-bench Verified task, GPT-5.1 costs $1.02 and Grok 4.5 $0.62.

Which has the bigger context window, GPT-5.1 or Grok 4.5?

Grok 4.5, with 500K tokens against 400K.

How many benchmarks is the GPT-5.1 vs Grok 4.5 comparison based on?

80 benchmarks have a result for both models as of October 22, 2026. GPT-5.1's coding index rests on 3 independent benchmarks and Grok 4.5's on 6. Where only one model has a result, the page says so instead of naming a winner.

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