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GPT-5.6 Terra vs Grok 4.6

Updated October 21, 2026. 116 benchmarks have a result for both. Coding is ranked on the Vibe Coding Index; every other board is shown as published.

Replace GPT-5.6 Terra Replace Grok 4.6
GPT-5.6 TerraOpenAI
Coding
69.0
Overall
42.1
Output $/M
$12.00
60
Grok 4.6xAI
Coding
76.4
Overall
44.3
Output $/M
$6.00
56
vs boards won of 116 shared

Decision reading

Pick Grok 4.6 for coding: it scores 76.4 on the Vibe Coding Index against 69.0 for GPT-5.6 Terra.

Pick GPT-5.6 Terra when a solved task costs $0.42 against $0.82, or when the context window is larger, 1.05M against 500K tokens.

Model AGPT-5.6 TerraOpenAI69.0/1002 independent benchmarks$0.42 per solved taskModel BGrok 4.6xAI76.4/1002 independent benchmarks$0.82 per solved task
Shared results
116
GPT-5.6 Terra only
8
Grok 4.6 only
7
Like-for-like categories
8 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-5.6 Terra 69.0 from 2 benchmarks, Grok 4.6 76.4 from 2 benchmarks.
Widest category
Math, 15.5 points apart on average over 6 shared benchmarks.
Widest single gap
IOI (Vals AI): GPT-5.6 Terra 87.6% against Grok 4.6 47.6%, 40.0 points apart on a 0 to 100 scale.
Output price
GPT-5.6 Terra $12.00 against Grok 4.6 $6.00 per million output tokens, 2.0x apart.
Context window
GPT-5.6 Terra takes 1.05M tokens, Grok 4.6 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-5.6 TerraBarsGrok 4.6Ties
Coding1013
Intelligence11
Agentic work414
Reasoning96
Math60
Knowledge65
Web design09
General248
All shared boards6056
CodingLike-for-likeFour of these boards feed the Vibe Coding Index1013
Coding benchmarks for GPT-5.6 Terra and Grok 4.6
BenchmarkGPT-5.6 TerraGrok 4.6Leader
LiveBench coding86.2%89.1%Grok 4.6
LMArena WebDev15221617Grok 4.6
AA Coding Index76.776.8Grok 4.6
LiveCodeBench (Vals AI)85.9%88.2%Grok 4.6
SWE-bench Verified (Vals AI)95.4%95.6%Grok 4.6
Terminal-Bench 4 (Vals AI)22.7%17.2%GPT-5.6 Terra
Vibe Code Bench (Vals AI)74.6%76.2%Grok 4.6
Code migration (Vals AI)47.8%44.6%GPT-5.6 Terra
ProgramBench (Vals AI)0.5%1.0%Grok 4.6
IOI (Vals AI)87.6%47.6%GPT-5.6 Terra
Terminal-Bench 2.1 (Vals AI)77.5%78.3%Grok 4.6
Vibe Code Bench 1-100 (Vals AI)14.8%14.8%GPT-5.6 Terra
SkillsBench (Vals AI)58.9%55.8%GPT-5.6 Terra
CyberBench (Vals AI)72.1%67.7%GPT-5.6 Terra
SciCode55.0%56.5%Grok 4.6
Terminal-Bench Hard (Artificial Analysis run)62.9%Not measuredOnly GPT-5.6 Terra measured
FrontierCode41.3%48.0%Grok 4.6
FrontierSWENot measured25.3%Only Grok 4.6 measured
WeirdML78.3%67.3%GPT-5.6 Terra
ALE-Bench1951.41508.1GPT-5.6 Terra
LMArena Text: coding14851466GPT-5.6 Terra
LMArena Text: software and IT14821457GPT-5.6 Terra
LMArena WebDev: React15131631Grok 4.6
LMArena WebDev: HTML15261597Grok 4.6
LMArena WebDev: from an image15411603Grok 4.6
Neither model has a result on the other 13 boards here
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index11
Intelligence benchmarks for GPT-5.6 Terra and Grok 4.6
BenchmarkGPT-5.6 TerraGrok 4.6Leader
AA Intelligence Index42.144.3Grok 4.6
Epoch Capabilities Index160.1156.6GPT-5.6 Terra
Agentic workLike-for-likePublic boards, shown as published, kept out of the index414
Agentic work benchmarks for GPT-5.6 Terra and Grok 4.6
BenchmarkGPT-5.6 TerraGrok 4.6Leader
AA Agentic Index43.253.0Grok 4.6
Design Arena: agents building web apps11201247Grok 4.6
Design Arena: agents building full-stack apps10611264Grok 4.6
Design Arena: agents building mobile apps11121234Grok 4.6
Design Arena: agents building Android apps10661297Grok 4.6
Design Arena: agents building Godot gamesNot measured1276Only Grok 4.6 measured
Design Arena: agents building games10821208Grok 4.6
Design Arena: HTML slides11081249Grok 4.6
Design Arena: PowerPoint slides11301241Grok 4.6
LiveBench research60.4%84.5%Grok 4.6
LiveBench browser84.0%64.0%GPT-5.6 Terra
LiveBench long agentic48.4%40.7%GPT-5.6 Terra
SREBench (Vals AI)9.5%Not measuredOnly GPT-5.6 Terra measured
Finance Agent (Vals AI)54.4%53.7%GPT-5.6 Terra
Tax Agent Bench (Vals AI)30.0%33.1%Grok 4.6
Legal Research Bench (Vals AI)41.4%48.1%Grok 4.6
Excel Modeling Benchmark (Vals AI)66.2%62.7%GPT-5.6 Terra
BioMysteryBench (Vals AI)Not measured72.2%Only Grok 4.6 measured
Terminal-Bench-Science (Vals AI)10.0%11.4%Grok 4.6
Vals Science IndexNot measured38.1%Only Grok 4.6 measured
Time Horizon Index (Vals AI)Not measured5.8%Only Grok 4.6 measured
τ²-Bench Telecom86.3%Not measuredOnly GPT-5.6 Terra measured
APEX-Agents58.2%65.3%Grok 4.6
BALROG53.2%Not measuredOnly GPT-5.6 Terra measured
Vending-Bench 2$7,343$9,047Grok 4.6
Neither model has a result on the other 14 boards here
ReasoningLike-for-likePublic boards, shown as published, kept out of the index96
Reasoning benchmarks for GPT-5.6 Terra and Grok 4.6
BenchmarkGPT-5.6 TerraGrok 4.6Leader
GPQA Diamond90.9%94.7%Grok 4.6
LiveBench reasoning90.6%91.2%Grok 4.6
MysteryMechanism (Vals AI)Not measured30.6%Only Grok 4.6 measured
MMMU Pro (Vals AI)86.5%Not measuredOnly GPT-5.6 Terra measured
GPQA Diamond (Artificial Analysis run)92.5%94.9%Grok 4.6
Humanity's Last Exam (Artificial Analysis run)42.9%44.1%Grok 4.6
GPQA Diamond (Epoch AI run)93.3%94.0%Grok 4.6
ARC-AGI96.5%87.5%GPT-5.6 Terra
ARC-AGI-283.9%67.1%GPT-5.6 Terra
SimpleBench48.9%75.9%Grok 4.6
Chess puzzles47.0%33.0%GPT-5.6 Terra
Mystery game puzzles35.0%34.0%GPT-5.6 Terra
EBR-benchNot measured30.5%Only Grok 4.6 measured
LMArena Text: hard prompts14691448GPT-5.6 Terra
LMArena Text: expert14961469GPT-5.6 Terra
LMArena Text: hard prompts in English14651445GPT-5.6 Terra
LMArena Vision: diagrams12951285GPT-5.6 Terra
LMArena Vision: homework13121283GPT-5.6 Terra
Neither model has a result on the other 3 boards here
MathLike-for-likePublic boards, shown as published, kept out of the index60
Math benchmarks for GPT-5.6 Terra and Grok 4.6
BenchmarkGPT-5.6 TerraGrok 4.6Leader
OTIS Mock AIME99.7%99.2%GPT-5.6 Terra
FrontierMath, tiers 1 to 386.0%66.0%GPT-5.6 Terra
FrontierMath, tier 470.7%31.7%GPT-5.6 Terra
ProofBench74.0%51.0%GPT-5.6 Terra
LMArena Text: math14651417GPT-5.6 Terra
LMArena Text: mathematical work14781464GPT-5.6 Terra
Neither model has a result on the other 7 boards here
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index65
Knowledge benchmarks for GPT-5.6 Terra and Grok 4.6
BenchmarkGPT-5.6 TerraGrok 4.6Leader
MMLU Pro86.7%89.4%Grok 4.6
LegalBench (Vals AI)85.1%86.3%Grok 4.6
CorpFin (Vals AI)65.3%66.2%Grok 4.6
TaxEval (Vals AI)76.2%71.1%GPT-5.6 Terra
MortgageTax (Vals AI)67.3%64.2%GPT-5.6 Terra
MedCode (Vals AI)43.4%44.7%Grok 4.6
SimpleQA Verified43.2%49.3%Grok 4.6
LMArena Text: science14521437GPT-5.6 Terra
LMArena Text: medicine and healthcare14301420GPT-5.6 Terra
LMArena Text: legal and government14611429GPT-5.6 Terra
LMArena Text: business and finance14481416GPT-5.6 Terra
Neither model has a result on the other 6 boards here
Web designLike-for-likePublic boards, shown as published, kept out of the index09
Web design benchmarks for GPT-5.6 Terra and Grok 4.6
BenchmarkGPT-5.6 TerraGrok 4.6Leader
Design Arena: websites12691289Grok 4.6
Design Arena: UI components12591294Grok 4.6
Design Arena: game dev12301296Grok 4.6
Design Arena: data viz12401283Grok 4.6
Design Arena: 3D11351277Grok 4.6
Design Arena: all code categories12411292Grok 4.6
Design Arena: SVG12201239Grok 4.6
Design Arena: ASCII art11771278Grok 4.6
LiveBench design76.0%79.8%Grok 4.6
GeneralLike-for-likePublic boards, shown as published, kept out of the index248
General benchmarks for GPT-5.6 Terra and Grok 4.6
BenchmarkGPT-5.6 TerraGrok 4.6Leader
LiveBench data analysis79.3%75.3%GPT-5.6 Terra
Public Benefits Bench (Vals AI)62.4%66.8%Grok 4.6
SAGE (Vals AI)47.0%28.9%GPT-5.6 Terra
MedScribe (Vals AI)82.9%86.5%Grok 4.6
Vals Multimodal Index65.1%Not measuredOnly GPT-5.6 Terra measured
IFBench71.2%Not measuredOnly GPT-5.6 Terra measured
Long context reasoning (AA-LCR)83.0%81.0%GPT-5.6 Terra
DTBench93.3%97.3%Grok 4.6
LMCA54.9%48.5%GPT-5.6 Terra
Surface Evolver Bench83.8%Not measuredOnly GPT-5.6 Terra measured
Furniture assembly54.2%40.0%GPT-5.6 Terra
LMArena Text14481429GPT-5.6 Terra
LMArena Text: instruction following14561431GPT-5.6 Terra
LMArena Text: creative writing14131426Grok 4.6
LMArena Vision12711263GPT-5.6 Terra
LMArena Text: English14491433GPT-5.6 Terra
LMArena Text: non-English14411420GPT-5.6 Terra
LMArena Text: Chinese15141476GPT-5.6 Terra
LMArena Text: German14601426GPT-5.6 Terra
LMArena Text: Japanese14541378GPT-5.6 Terra
LMArena Text: Korean14271391GPT-5.6 Terra
LMArena Text: French14661455GPT-5.6 Terra
LMArena Text: Spanish14511414GPT-5.6 Terra
LMArena Text: Russian14521421GPT-5.6 Terra
LMArena Text: Polish14461430GPT-5.6 Terra
LMArena Text: multi-turn14531425GPT-5.6 Terra
LMArena Text: longer queries14541456Grok 4.6
LMArena Text: writing and language14311429GPT-5.6 Terra
LMArena Text: entertainment and media14181421Grok 4.6
LMArena Vision: English12721270GPT-5.6 Terra
LMArena Vision: Chinese13371289GPT-5.6 Terra
LMArena Vision: reading text12781272GPT-5.6 Terra
LMArena Vision: humor12361270Grok 4.6
LMArena Vision: creative writing12481262Grok 4.6
LMArena Document14721452GPT-5.6 Terra
Neither model has a result on the other 11 boards here
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
Image generation benchmarks for GPT-5.6 Terra and Grok 4.6
BenchmarkGPT-5.6 TerraGrok 4.6Leader
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-5.6 Terra$0.0080Fits in one request
Grok 4.6$0.0050Fits in one request

Grok 4.6 costs less

Repository review

50K input + 3K output tokens

GPT-5.6 Terra$0.136Fits in one request
Grok 4.6$0.118Fits in one request

Grok 4.6 costs less

Agent loop

200K input + 10K output tokens

GPT-5.6 Terra$0.520Fits in one request
Grok 4.6$0.460Fits in one request

Grok 4.6 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-5.6 Terra and Grok 4.6
SpecificationOpenAI GPT-5.6 TerraSpaceXAI Grok 4.6
MakerOpenAIxAI
WeightsNo public weights listedNo public weights listed
ReleasedJuly 9, 2026August 12, 2026
Context window1.05M500K
Input $/Mtok$2.00$2.00
Output $/Mtok$12.00$6.00
Coding index69.076.4
Independent measurements behind it22
Cost per solved task$0.42$0.82
SourceOpenRouter listingOpenRouter listing

Questions

Is GPT-5.6 Terra better than Grok 4.6 for coding?

Pick Grok 4.6 for coding: it scores 76.4 on the Vibe Coding Index against 69.0 for GPT-5.6 Terra. Pick GPT-5.6 Terra when a solved task costs $0.42 against $0.82, or when the context window is larger, 1.05M against 500K tokens.

Which is cheaper, GPT-5.6 Terra or Grok 4.6?

GPT-5.6 Terra costs $2.00 per million input tokens and $12.00 per million output tokens; Grok 4.6 costs $2.00 and $6.00. Per solved SWE-bench Verified task, GPT-5.6 Terra costs $0.42 and Grok 4.6 $0.82.

Which has the bigger context window, GPT-5.6 Terra or Grok 4.6?

GPT-5.6 Terra, with 1.05M tokens against 500K.

How many benchmarks is the GPT-5.6 Terra vs Grok 4.6 comparison based on?

116 benchmarks have a result for both models as of October 21, 2026. GPT-5.6 Terra's coding index rests on 2 independent benchmarks and Grok 4.6's on 2. Where only one model has a result, the page says so instead of naming a winner.

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