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GPT-5.5 vs Grok 4.3

GPT-5.5 leads Grok 4.3 on coding, 71.3 to 37.4 on the Vibe Coding Index, and Grok 4.3 costs 12.0x less per output token ($2.50 vs $30.00 per million). Updated October 22, 2026; 103 benchmarks have a result for both.

Replace GPT-5.5 Replace Grok 4.3
GPT-5.5OpenAI
Coding
71.3
Overall
69.2
Output $/M
$30.00
97
Grok 4.3xAI
Coding
37.4
Overall
53.1
Output $/M
$2.50
6
vs boards won of 103 shared

GPT-5.5 or Grok 4.3: which to pick

Pick GPT-5.5 for coding: it scores 71.3 on the Vibe Coding Index against 37.4 for Grok 4.3.

Pick Grok 4.3 for output tokens 12.0x cheaper ($2.50 vs $30.00 per million) and a lower cost per solved task ($0.31 against $1.65).

Model AGPT-5.5OpenAI71.3/1005 independent benchmarks$1.65 per solved taskModel BGrok 4.3xAI37.4/1003 independent benchmarks$0.31 per solved task
Shared results
103
GPT-5.5 only
31
Grok 4.3 only
2
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-5.5 71.3 from 5 benchmarks, Grok 4.3 37.4 from 3 benchmarks.
Widest category
Math, 30.3 points apart on average over 6 shared benchmarks.
Widest single gap
FrontierMath, tier 4: GPT-5.5 72.5% against Grok 4.3 14.6%, 57.9 points apart on a 0 to 100 scale.
Output price
GPT-5.5 $30.00 against Grok 4.3 $2.50 per million output tokens, 12.0x apart.
Context window
GPT-5.5 takes 1.05M 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-5.5BarsGrok 4.3Ties
Coding180
Intelligence10
Agentic work132
Reasoning110
Math51
Knowledge102
Web design80
General311
All shared boards976
CodingLike-for-likeSix of these boards feed the Vibe Coding Index180
Coding benchmarks for GPT-5.5 and Grok 4.3
BenchmarkGPT-5.5Grok 4.3Leader
LiveBench coding85.1%Not measuredOnly GPT-5.5 measured
LMArena WebDev15131358GPT-5.5
AA Coding Index74.942.2GPT-5.5
LiveCodeBench (Vals AI)85.3%84.5%GPT-5.5
SWE-bench Verified (Vals AI)82.6%71.4%GPT-5.5
Vibe Code Bench (Vals AI)69.8%19.4%GPT-5.5
Code migration (Vals AI)45.2%6.8%GPT-5.5
ProgramBench (Vals AI)0.5%0.0%GPT-5.5
Terminal-Bench 2.1 (Vals AI)76.4%42.0%GPT-5.5
SkillsBench (Vals AI)62.5%40.6%GPT-5.5
SciCode56.1%48.3%GPT-5.5
Terminal-Bench Hard (Artificial Analysis run)60.6%37.9%GPT-5.5
Terminal-Bench84.7%Not measuredOnly GPT-5.5 measured
FrontierCode43.0%Not measuredOnly GPT-5.5 measured
GSO-Bench40.2%Not measuredOnly GPT-5.5 measured
WeirdML84.9%49.9%GPT-5.5
MirrorCode10.0%Not measuredOnly GPT-5.5 measured
ALE-Bench1943.0944.2GPT-5.5
LMArena Text: coding14941415GPT-5.5
LMArena Text: software and IT14931416GPT-5.5
LMArena WebDev: React15061353GPT-5.5
LMArena WebDev: HTML15431367GPT-5.5
LMArena WebDev: from an image15321375GPT-5.5
Neither model has a result on the other 16 boards here
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index10
Intelligence benchmarks for GPT-5.5 and Grok 4.3
BenchmarkGPT-5.5Grok 4.3Leader
AA Intelligence Index38.424.9GPT-5.5
Epoch Capabilities Index159.7Not measuredOnly GPT-5.5 measured
Agentic workLike-for-likePublic boards, shown as published, kept out of the index132
Agentic work benchmarks for GPT-5.5 and Grok 4.3
BenchmarkGPT-5.5Grok 4.3Leader
AA Agentic Index36.415.5GPT-5.5
Design Arena: agents building web apps11171126Grok 4.3
Design Arena: agents building full-stack apps10891006GPT-5.5
Design Arena: agents building mobile apps11421058GPT-5.5
Design Arena: agents building Android apps1164962GPT-5.5
Design Arena: agents building Godot games1173914GPT-5.5
Design Arena: agents building games11791007GPT-5.5
Design Arena: HTML slides1017959GPT-5.5
Design Arena: PowerPoint slides1084988GPT-5.5
Design Arena: spreadsheetsNot measured879Only Grok 4.3 measured
LiveBench research61.6%Not measuredOnly GPT-5.5 measured
LiveBench browser48.0%Not measuredOnly GPT-5.5 measured
LiveBench long agentic44.6%Not measuredOnly GPT-5.5 measured
SREBench (Vals AI)3.8%Not measuredOnly GPT-5.5 measured
Finance Agent (Vals AI)51.8%37.7%GPT-5.5
Tax Agent Bench (Vals AI)21.8%6.2%GPT-5.5
Legal Research Bench (Vals AI)40.4%15.4%GPT-5.5
Excel Modeling Benchmark (Vals AI)64.5%18.4%GPT-5.5
Time Horizon Index (Vals AI)8.3%Not measuredOnly GPT-5.5 measured
τ²-Bench Telecom93.9%97.7%Grok 4.3
APEX-Agents55.1%Not measuredOnly GPT-5.5 measured
Remote Labor Index6.3%Not measuredOnly GPT-5.5 measured
OSWorld 2.013.0%Not measuredOnly GPT-5.5 measured
DeepResearch Bench54.0%Not measuredOnly GPT-5.5 measured
PostTrainBench27.2%Not measuredOnly GPT-5.5 measured
Vending-Bench 2$7,524$35GPT-5.5
LMArena SearchNot measured1166Only Grok 4.3 measured
Neither model has a result on the other 14 boards here
ReasoningLike-for-likePublic boards, shown as published, kept out of the index110
Reasoning benchmarks for GPT-5.5 and Grok 4.3
BenchmarkGPT-5.5Grok 4.3Leader
GPQA Diamond93.2%91.4%GPT-5.5
LiveBench reasoning89.7%Not measuredOnly GPT-5.5 measured
MMMU Pro (Vals AI)88.3%83.1%GPT-5.5
GPQA Diamond (Artificial Analysis run)93.5%90.1%GPT-5.5
Humanity's Last Exam (Artificial Analysis run)45.8%37.2%GPT-5.5
GPQA Diamond (Epoch AI run)90.7%88.8%GPT-5.5
ARC-AGI95.0%Not measuredOnly GPT-5.5 measured
ARC-AGI-285.0%Not measuredOnly GPT-5.5 measured
SimpleBench69.0%Not measuredOnly GPT-5.5 measured
Chess puzzles63.0%18.0%GPT-5.5
Mystery game puzzles56.0%Not measuredOnly GPT-5.5 measured
EBR-bench34.3%Not measuredOnly GPT-5.5 measured
LMArena Text: hard prompts14891396GPT-5.5
LMArena Text: expert15071384GPT-5.5
LMArena Text: hard prompts in English14831402GPT-5.5
LMArena Vision: diagrams13251241GPT-5.5
LMArena Vision: homework13321241GPT-5.5
Kagi LLM Benchmark88.8%Not measuredOnly GPT-5.5 measured
Neither model has a result on the other 4 boards here
MathLike-for-likePublic boards, shown as published, kept out of the index51
Math benchmarks for GPT-5.5 and Grok 4.3
BenchmarkGPT-5.5Grok 4.3Leader
OTIS Mock AIME84.4%93.3%Grok 4.3
FrontierMath, tiers 1 to 385.3%42.8%GPT-5.5
FrontierMath, tier 472.5%14.6%GPT-5.5
ProofBench50.0%11.0%GPT-5.5
LMArena Text: math14871387GPT-5.5
LMArena Text: mathematical work14961396GPT-5.5
Neither model has a result on the other 7 boards here
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index102
Knowledge benchmarks for GPT-5.5 and Grok 4.3
BenchmarkGPT-5.5Grok 4.3Leader
MMLU Pro88.1%85.8%GPT-5.5
LegalBench (Vals AI)86.5%84.5%GPT-5.5
CaseLaw (Vals AI)66.2%79.3%Grok 4.3
CorpFin (Vals AI)68.4%68.5%Grok 4.3
TaxEval (Vals AI)75.0%70.8%GPT-5.5
MortgageTax (Vals AI)68.8%48.3%GPT-5.5
MedCode (Vals AI)49.1%38.1%GPT-5.5
SimpleQA Verified63.0%33.2%GPT-5.5
LMArena Text: science14851399GPT-5.5
LMArena Text: medicine and healthcare14651384GPT-5.5
LMArena Text: legal and government14911386GPT-5.5
LMArena Text: business and finance14781381GPT-5.5
FACTS Benchmark Suite66.7%Not measuredOnly GPT-5.5 measured
Neither model has a result on the other 5 boards here
Web designLike-for-likePublic boards, shown as published, kept out of the index80
Web design benchmarks for GPT-5.5 and Grok 4.3
BenchmarkGPT-5.5Grok 4.3Leader
Design Arena: websites12561196GPT-5.5
Design Arena: UI components12571190GPT-5.5
Design Arena: game dev12931173GPT-5.5
Design Arena: data viz12641179GPT-5.5
Design Arena: 3D11971124GPT-5.5
Design Arena: all code categories12601186GPT-5.5
Design Arena: SVG12341080GPT-5.5
Design Arena: ASCII art12551125GPT-5.5
LiveBench design70.3%Not measuredOnly GPT-5.5 measured
GeneralLike-for-likePublic boards, shown as published, kept out of the index311
General benchmarks for GPT-5.5 and Grok 4.3
BenchmarkGPT-5.5Grok 4.3Leader
LiveBench data analysis81.6%Not measuredOnly GPT-5.5 measured
Public Benefits Bench (Vals AI)60.9%51.7%GPT-5.5
SAGE (Vals AI)51.5%19.7%GPT-5.5
MedScribe (Vals AI)86.9%74.4%GPT-5.5
Vals Multimodal Index68.1%43.3%GPT-5.5
IFBench75.9%83.3%Grok 4.3
Long context reasoning (AA-LCR)84.3%75.0%GPT-5.5
DTBench96.0%90.7%GPT-5.5
LMCA54.3%38.3%GPT-5.5
Surface Evolver Bench88.1%Not measuredOnly GPT-5.5 measured
Furniture assembly44.2%Not measuredOnly GPT-5.5 measured
ExploitBench47.4%Not measuredOnly GPT-5.5 measured
CL-bench Life22.2%Not measuredOnly GPT-5.5 measured
LMArena Text14711397GPT-5.5
LMArena Text: instruction following14781366GPT-5.5
LMArena Text: creative writing14551380GPT-5.5
LMArena Vision12971229GPT-5.5
LMArena Text: English14701404GPT-5.5
LMArena Text: non-English14671385GPT-5.5
LMArena Text: Chinese15341422GPT-5.5
LMArena Text: German14801395GPT-5.5
LMArena Text: Japanese14991379GPT-5.5
LMArena Text: Korean14601354GPT-5.5
LMArena Text: French14851411GPT-5.5
LMArena Text: Spanish14681399GPT-5.5
LMArena Text: Russian14731399GPT-5.5
LMArena Text: Polish14651398GPT-5.5
LMArena Text: multi-turn14761406GPT-5.5
LMArena Text: longer queries14841393GPT-5.5
LMArena Text: writing and language14661385GPT-5.5
LMArena Text: entertainment and media14491370GPT-5.5
LMArena Vision: English12921235GPT-5.5
LMArena Vision: Chinese13601257GPT-5.5
LMArena Vision: reading text13061235GPT-5.5
LMArena Vision: humor12931222GPT-5.5
LMArena Vision: recognizing things12311217GPT-5.5
LMArena Vision: creative writing13011237GPT-5.5
LMArena Document1486Not measuredOnly GPT-5.5 measured
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-5.5 and Grok 4.3
BenchmarkGPT-5.5Grok 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-5.5$0.020Fits in one request
Grok 4.3$0.0025Fits in one request

Grok 4.3 costs less

Repository review

50K input + 3K output tokens

GPT-5.5$0.340Fits in one request
Grok 4.3$0.070Fits in one request

Grok 4.3 costs less

Agent loop

200K input + 10K output tokens

GPT-5.5$1.30Fits 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-5.5 and Grok 4.3
SpecificationOpenAI GPT-5.5SpaceXAI Grok 4.3
MakerOpenAIxAI
WeightsNo public weights listedNo public weights listed
ReleasedApril 24, 2026April 30, 2026
Context window1.05M1M
Input $/Mtok$5.00$1.25
Output $/Mtok$30.00$2.50
Coding index71.337.4
Independent measurements behind it53
Cost per solved task$1.65$0.31
SourceOpenRouter listingOpenRouter listing

Questions

Is GPT-5.5 better than Grok 4.3 for coding?

Pick GPT-5.5 for coding: it scores 71.3 on the Vibe Coding Index against 37.4 for Grok 4.3. Pick Grok 4.3 for output tokens 12.0x cheaper ($2.50 vs $30.00 per million) and a lower cost per solved task ($0.31 against $1.65).

Which is cheaper, GPT-5.5 or Grok 4.3?

GPT-5.5 costs $5.00 per million input tokens and $30.00 per million output tokens; Grok 4.3 costs $1.25 and $2.50. Per solved SWE-bench Verified task, GPT-5.5 costs $1.65 and Grok 4.3 $0.31.

Which has the bigger context window, GPT-5.5 or Grok 4.3?

GPT-5.5, with 1.05M tokens against 1M.

How many benchmarks is the GPT-5.5 vs Grok 4.3 comparison based on?

103 benchmarks have a result for both models as of October 22, 2026. GPT-5.5's coding index rests on 5 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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