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GPT-5.6 Terra vs Grok 4.3

GPT-5.6 Terra leads Grok 4.3 on coding, 63.9 to 37.4 on the Vibe Coding Index, and Grok 4.3 costs 4.8x less per output token ($2.50 vs $12.00 per million). Updated October 22, 2026; 100 benchmarks have a result for both.

Replace GPT-5.6 Terra Replace Grok 4.3
GPT-5.6 TerraOpenAI
Coding
63.9
Overall
68.1
Output $/M
$12.00
95
Grok 4.3xAI
Coding
37.4
Overall
53.1
Output $/M
$2.50
5
vs boards won of 100 shared

GPT-5.6 Terra or Grok 4.3: which to pick

Pick GPT-5.6 Terra for coding: it scores 63.9 on the Vibe Coding Index against 37.4 for Grok 4.3.

Pick Grok 4.3 for output tokens 4.8x cheaper ($2.50 vs $12.00 per million) and a lower cost per solved task ($0.31 against $0.42).

Model AGPT-5.6 TerraOpenAI63.9/1006 independent benchmarks$0.42 per solved taskModel BGrok 4.3xAI37.4/1003 independent benchmarks$0.31 per solved task
Shared results
100
GPT-5.6 Terra only
27
Grok 4.3 only
5
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-5.6 Terra 63.9 from 6 benchmarks, Grok 4.3 37.4 from 3 benchmarks.
Widest category
Math, 32.6 points apart on average over 6 shared benchmarks.
Widest single gap
ProofBench: GPT-5.6 Terra 74.0% against Grok 4.3 11.0%, 63.0 points apart on a 0 to 100 scale.
Output price
GPT-5.6 Terra $12.00 against Grok 4.3 $2.50 per million output tokens, 4.8x apart.
Context window
GPT-5.6 Terra 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-5.6 TerraBarsGrok 4.3Ties
Coding180
Intelligence10
Agentic work122
Reasoning101
Math60
Knowledge101
Web design80
General301
All shared boards955
CodingLike-for-likeSix of these boards feed the Vibe Coding Index180
Coding benchmarks for GPT-5.6 Terra and Grok 4.3
BenchmarkGPT-5.6 TerraGrok 4.3Leader
LiveBench coding86.2%Not measuredOnly GPT-5.6 Terra measured
LMArena WebDev15221358GPT-5.6 Terra
AA Coding Index76.742.2GPT-5.6 Terra
LiveCodeBench (Vals AI)85.9%84.5%GPT-5.6 Terra
SWE-bench Verified (Vals AI)95.4%71.4%GPT-5.6 Terra
Terminal-Bench 4 (Vals AI)22.7%Not measuredOnly GPT-5.6 Terra measured
Vibe Code Bench (Vals AI)74.6%19.4%GPT-5.6 Terra
Code migration (Vals AI)47.8%6.8%GPT-5.6 Terra
ProgramBench (Vals AI)0.5%0.0%GPT-5.6 Terra
IOI (Vals AI)87.6%Not measuredOnly GPT-5.6 Terra measured
Terminal-Bench 2.1 (Vals AI)77.5%42.0%GPT-5.6 Terra
Vibe Code Bench 1-100 (Vals AI)14.8%Not measuredOnly GPT-5.6 Terra measured
SkillsBench (Vals AI)58.9%40.6%GPT-5.6 Terra
CyberBench (Vals AI)72.1%Not measuredOnly GPT-5.6 Terra measured
SciCode55.0%48.3%GPT-5.6 Terra
Terminal-Bench Hard (Artificial Analysis run)62.9%37.9%GPT-5.6 Terra
FrontierCode41.3%Not measuredOnly GPT-5.6 Terra measured
WeirdML78.3%49.9%GPT-5.6 Terra
ALE-Bench1951.4944.2GPT-5.6 Terra
LMArena Text: coding14851415GPT-5.6 Terra
LMArena Text: software and IT14821416GPT-5.6 Terra
LMArena WebDev: React15131353GPT-5.6 Terra
LMArena WebDev: HTML15261367GPT-5.6 Terra
LMArena WebDev: from an image15411375GPT-5.6 Terra
SciCode10.8%Not measuredOnly GPT-5.6 Terra measured
Neither model has a result on the other 14 boards here
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index10
Intelligence benchmarks for GPT-5.6 Terra and Grok 4.3
BenchmarkGPT-5.6 TerraGrok 4.3Leader
AA Intelligence Index42.124.9GPT-5.6 Terra
Epoch Capabilities Index160.1Not measuredOnly GPT-5.6 Terra measured
Agentic workLike-for-likePublic boards, shown as published, kept out of the index122
Agentic work benchmarks for GPT-5.6 Terra and Grok 4.3
BenchmarkGPT-5.6 TerraGrok 4.3Leader
AA Agentic Index43.215.5GPT-5.6 Terra
Design Arena: agents building web apps11201126Grok 4.3
Design Arena: agents building full-stack apps10611006GPT-5.6 Terra
Design Arena: agents building mobile apps11111058GPT-5.6 Terra
Design Arena: agents building Android apps1062962GPT-5.6 Terra
Design Arena: agents building Godot gamesNot measured914Only Grok 4.3 measured
Design Arena: agents building games10831007GPT-5.6 Terra
Design Arena: HTML slides1058959GPT-5.6 Terra
Design Arena: PowerPoint slides1105988GPT-5.6 Terra
Design Arena: spreadsheetsNot measured879Only Grok 4.3 measured
LiveBench research60.4%Not measuredOnly GPT-5.6 Terra measured
LiveBench browser84.0%Not measuredOnly GPT-5.6 Terra measured
LiveBench long agentic48.4%Not measuredOnly GPT-5.6 Terra measured
SREBench (Vals AI)9.5%Not measuredOnly GPT-5.6 Terra measured
Finance Agent (Vals AI)54.4%37.7%GPT-5.6 Terra
Tax Agent Bench (Vals AI)30.0%6.2%GPT-5.6 Terra
Legal Research Bench (Vals AI)41.4%15.4%GPT-5.6 Terra
Excel Modeling Benchmark (Vals AI)66.2%18.4%GPT-5.6 Terra
Terminal-Bench-Science (Vals AI)10.0%Not measuredOnly GPT-5.6 Terra measured
τ²-Bench Telecom86.3%97.7%Grok 4.3
APEX-Agents58.2%Not measuredOnly GPT-5.6 Terra measured
BALROG53.2%Not measuredOnly GPT-5.6 Terra measured
Vending-Bench 2$7,343$35GPT-5.6 Terra
LMArena SearchNot measured1166Only Grok 4.3 measured
Neither model has a result on the other 17 boards here
ReasoningLike-for-likePublic boards, shown as published, kept out of the index101
Reasoning benchmarks for GPT-5.6 Terra and Grok 4.3
BenchmarkGPT-5.6 TerraGrok 4.3Leader
GPQA Diamond90.9%91.4%Grok 4.3
LiveBench reasoning90.6%Not measuredOnly GPT-5.6 Terra measured
MMMU Pro (Vals AI)86.5%83.1%GPT-5.6 Terra
GPQA Diamond (Artificial Analysis run)92.5%90.1%GPT-5.6 Terra
Humanity's Last Exam (Artificial Analysis run)42.9%37.2%GPT-5.6 Terra
GPQA Diamond (Epoch AI run)93.3%88.8%GPT-5.6 Terra
ARC-AGI96.5%Not measuredOnly GPT-5.6 Terra measured
ARC-AGI-283.9%Not measuredOnly GPT-5.6 Terra measured
SimpleBench48.9%Not measuredOnly GPT-5.6 Terra measured
Chess puzzles47.0%18.0%GPT-5.6 Terra
Mystery game puzzles35.0%Not measuredOnly GPT-5.6 Terra measured
LMArena Text: hard prompts14691396GPT-5.6 Terra
LMArena Text: expert14961384GPT-5.6 Terra
LMArena Text: hard prompts in English14651402GPT-5.6 Terra
LMArena Vision: diagrams12951241GPT-5.6 Terra
LMArena Vision: homework13121241GPT-5.6 Terra
Kagi LLM Benchmark51.3%Not measuredOnly GPT-5.6 Terra measured
Neither model has a result on the other 5 boards here
MathLike-for-likePublic boards, shown as published, kept out of the index60
Math benchmarks for GPT-5.6 Terra and Grok 4.3
BenchmarkGPT-5.6 TerraGrok 4.3Leader
OTIS Mock AIME99.7%93.3%GPT-5.6 Terra
FrontierMath, tiers 1 to 386.0%42.8%GPT-5.6 Terra
FrontierMath, tier 470.7%14.6%GPT-5.6 Terra
ProofBench74.0%11.0%GPT-5.6 Terra
LMArena Text: math14651387GPT-5.6 Terra
LMArena Text: mathematical work14781396GPT-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 index101
Knowledge benchmarks for GPT-5.6 Terra and Grok 4.3
BenchmarkGPT-5.6 TerraGrok 4.3Leader
MMLU Pro86.7%85.8%GPT-5.6 Terra
LegalBench (Vals AI)85.1%84.5%GPT-5.6 Terra
CaseLaw (Vals AI)Not measured79.3%Only Grok 4.3 measured
CorpFin (Vals AI)65.3%68.5%Grok 4.3
TaxEval (Vals AI)76.2%70.8%GPT-5.6 Terra
MortgageTax (Vals AI)67.3%48.3%GPT-5.6 Terra
MedCode (Vals AI)43.4%38.1%GPT-5.6 Terra
SimpleQA Verified43.2%33.2%GPT-5.6 Terra
LMArena Text: science14521399GPT-5.6 Terra
LMArena Text: medicine and healthcare14301384GPT-5.6 Terra
LMArena Text: legal and government14611386GPT-5.6 Terra
LMArena Text: business and finance14481381GPT-5.6 Terra
FACTS Benchmark Suite52.0%Not measuredOnly GPT-5.6 Terra 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-5.6 Terra and Grok 4.3
BenchmarkGPT-5.6 TerraGrok 4.3Leader
Design Arena: websites12681196GPT-5.6 Terra
Design Arena: UI components12561190GPT-5.6 Terra
Design Arena: game dev12291173GPT-5.6 Terra
Design Arena: data viz12401179GPT-5.6 Terra
Design Arena: 3D11341124GPT-5.6 Terra
Design Arena: all code categories12411186GPT-5.6 Terra
Design Arena: SVG12191080GPT-5.6 Terra
Design Arena: ASCII art11771125GPT-5.6 Terra
LiveBench design76.0%Not measuredOnly GPT-5.6 Terra measured
GeneralLike-for-likePublic boards, shown as published, kept out of the index301
General benchmarks for GPT-5.6 Terra and Grok 4.3
BenchmarkGPT-5.6 TerraGrok 4.3Leader
LiveBench data analysis79.3%Not measuredOnly GPT-5.6 Terra measured
Public Benefits Bench (Vals AI)62.4%51.7%GPT-5.6 Terra
SAGE (Vals AI)47.0%19.7%GPT-5.6 Terra
MedScribe (Vals AI)82.9%74.4%GPT-5.6 Terra
Vals Multimodal Index65.1%43.3%GPT-5.6 Terra
IFBench71.2%83.3%Grok 4.3
Long context reasoning (AA-LCR)83.0%75.0%GPT-5.6 Terra
DTBench93.3%90.7%GPT-5.6 Terra
LMCA54.9%38.3%GPT-5.6 Terra
Surface Evolver Bench83.8%Not measuredOnly GPT-5.6 Terra measured
Furniture assembly54.2%Not measuredOnly GPT-5.6 Terra measured
LMArena Text14481397GPT-5.6 Terra
LMArena Text: instruction following14561366GPT-5.6 Terra
LMArena Text: creative writing14131380GPT-5.6 Terra
LMArena Vision12711229GPT-5.6 Terra
LMArena Text: English14491404GPT-5.6 Terra
LMArena Text: non-English14411385GPT-5.6 Terra
LMArena Text: Chinese15141422GPT-5.6 Terra
LMArena Text: German14601395GPT-5.6 Terra
LMArena Text: Japanese14541379GPT-5.6 Terra
LMArena Text: Korean14271354GPT-5.6 Terra
LMArena Text: French14661411GPT-5.6 Terra
LMArena Text: Spanish14511399GPT-5.6 Terra
LMArena Text: Russian14521399GPT-5.6 Terra
LMArena Text: Polish14461398GPT-5.6 Terra
LMArena Text: multi-turn14531406GPT-5.6 Terra
LMArena Text: longer queries14541393GPT-5.6 Terra
LMArena Text: writing and language14311385GPT-5.6 Terra
LMArena Text: entertainment and media14181370GPT-5.6 Terra
LMArena Vision: English12721235GPT-5.6 Terra
LMArena Vision: Chinese13371257GPT-5.6 Terra
LMArena Vision: reading text12781235GPT-5.6 Terra
LMArena Vision: humor12361222GPT-5.6 Terra
LMArena Vision: recognizing thingsNot measured1217Only Grok 4.3 measured
LMArena Vision: creative writing12481237GPT-5.6 Terra
LMArena Document1472Not measuredOnly GPT-5.6 Terra measured
Neither model has a result on the other 10 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 4.3
BenchmarkGPT-5.6 TerraGrok 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-5.6 Terra$0.0080Fits in one request
Grok 4.3$0.0025Fits in one request

Grok 4.3 costs less

Repository review

50K input + 3K output tokens

GPT-5.6 Terra$0.136Fits in one request
Grok 4.3$0.070Fits in one request

Grok 4.3 costs less

Agent loop

200K input + 10K output tokens

GPT-5.6 Terra$0.520Fits 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-5.6 Terra and Grok 4.3
SpecificationOpenAI GPT-5.6 TerraSpaceXAI Grok 4.3
MakerOpenAIxAI
WeightsNo public weights listedNo public weights listed
ReleasedJuly 9, 2026April 30, 2026
Context window1.05M1M
Input $/Mtok$2.00$1.25
Output $/Mtok$12.00$2.50
Coding index63.937.4
Independent measurements behind it63
Cost per solved task$0.42$0.31
SourceOpenRouter listingOpenRouter listing

Questions

Is GPT-5.6 Terra better than Grok 4.3 for coding?

Pick GPT-5.6 Terra for coding: it scores 63.9 on the Vibe Coding Index against 37.4 for Grok 4.3. Pick Grok 4.3 for output tokens 4.8x cheaper ($2.50 vs $12.00 per million) and a lower cost per solved task ($0.31 against $0.42).

Which is cheaper, GPT-5.6 Terra or Grok 4.3?

GPT-5.6 Terra costs $2.00 per million input tokens and $12.00 per million output tokens; Grok 4.3 costs $1.25 and $2.50. Per solved SWE-bench Verified task, GPT-5.6 Terra costs $0.42 and Grok 4.3 $0.31.

Which has the bigger context window, GPT-5.6 Terra or Grok 4.3?

GPT-5.6 Terra, with 1.05M tokens against 1M.

How many benchmarks is the GPT-5.6 Terra vs Grok 4.3 comparison based on?

100 benchmarks have a result for both models as of October 22, 2026. GPT-5.6 Terra's coding index rests on 6 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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