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GPT-6 Astra vs Grok 4.5

GPT-6 Astra leads Grok 4.5 on coding, 85.1 to 58.6 on the Vibe Coding Index, and Grok 4.5 costs 8.3x less per output token ($6.00 vs $50.00 per million). Updated October 22, 2026; 103 benchmarks have a result for both.

Replace GPT-6 Astra Replace Grok 4.5
GPT-6 AstraOpenAI
Coding
85.1
Overall
83.0
Output $/M
$50.00
76
Grok 4.5xAI
Coding
58.6
Overall
62.1
Output $/M
$6.00
27
vs boards won of 103 shared

GPT-6 Astra or Grok 4.5: which to pick

Pick GPT-6 Astra for coding: it scores 85.1 on the Vibe Coding Index against 58.6 for Grok 4.5, though on 5 benchmarks against 6.

Pick Grok 4.5 for output tokens 8.3x cheaper ($6.00 vs $50.00 per million) and work measured by LiveBench coding or CyberBench (Vals AI), where it leads.

Model AGPT-6 AstraOpenAI85.1/1005 independent benchmarksNo cost per solved taskModel BGrok 4.5xAI58.6/1006 independent benchmarks$0.62 per solved task
Shared results
103
GPT-6 Astra only
26
Grok 4.5 only
21
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-6 Astra 85.1 from 5 benchmarks, Grok 4.5 58.6 from 6 benchmarks.
Widest category
Math, 32.7 points apart on average over 7 shared benchmarks.
Widest single gap
Time Horizon Index (Vals AI): GPT-6 Astra 90.5% against Grok 4.5 6.3%, 84.2 points apart on a 0 to 100 scale.
Output price
GPT-6 Astra $50.00 against Grok 4.5 $6.00 per million output tokens, 8.3x apart.
Context window
GPT-6 Astra takes 1.05M 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-6 AstraBarsGrok 4.5Ties
Coding182
Intelligence20
Agentic work152
Reasoning111
Math70
Knowledge34
Web design90
General1118
All shared boards7627
CodingLike-for-likeSix of these boards feed the Vibe Coding Index182
Coding benchmarks for GPT-6 Astra and Grok 4.5
BenchmarkGPT-6 AstraGrok 4.5Leader
LiveBench coding93.7%94.3%Grok 4.5
LMArena WebDev17741553GPT-6 Astra
AA Coding Index76.972.4GPT-6 Astra
LiveCodeBench (Vals AI)Not measured87.3%Only Grok 4.5 measured
SWE-bench Verified (Vals AI)Not measured86.6%Only Grok 4.5 measured
Terminal-Bench 4 (Vals AI)59.6%8.6%GPT-6 Astra
Vibe Code Bench (Vals AI)89.6%69.0%GPT-6 Astra
Code migration (Vals AI)67.7%36.6%GPT-6 Astra
ProgramBench (Vals AI)5.5%0.0%GPT-6 Astra
IOI (Vals AI)100.0%40.6%GPT-6 Astra
Terminal-Bench 2.1 (Vals AI)87.3%67.8%GPT-6 Astra
SWE-bench Multimodal (Vals AI)43.3%Not measuredOnly GPT-6 Astra measured
Vibe Code Bench 1-100 (Vals AI)27.6%Not measuredOnly GPT-6 Astra measured
SkillsBench (Vals AI)Not measured66.0%Only Grok 4.5 measured
CyberBench (Vals AI)41.1%71.0%Grok 4.5
SciCode56.5%55.0%GPT-6 Astra
FrontierCode53.3%42.4%GPT-6 Astra
FrontierSWE65.5%Not measuredOnly GPT-6 Astra measured
GSO-Bench79.4%Not measuredOnly GPT-6 Astra measured
WeirdML93.3%46.4%GPT-6 Astra
MirrorCode46.7%Not measuredOnly GPT-6 Astra measured
ALE-Bench2951.31309.3GPT-6 Astra
LMArena Text: coding14891474GPT-6 Astra
LMArena Text: software and IT14741471GPT-6 Astra
LMArena WebDev: React17981556GPT-6 Astra
LMArena WebDev: HTML17751567GPT-6 Astra
LMArena WebDev: from an image17261562GPT-6 Astra
SciCode12.3%6.5%GPT-6 Astra
SWE-Bench Pro V296.9%Not measuredOnly GPT-6 Astra measured
SWE Atlas: Codebase QnA59.1%Not measuredOnly GPT-6 Astra measured
SWE Atlas: Refactoring59.1%Not measuredOnly GPT-6 Astra measured
SWE Atlas: Test Writing50.7%Not measuredOnly GPT-6 Astra measured
Neither model has a result on the other 11 boards here
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index20
Intelligence benchmarks for GPT-6 Astra and Grok 4.5
BenchmarkGPT-6 AstraGrok 4.5Leader
AA Intelligence Index52.738.8GPT-6 Astra
Epoch Capabilities Index168.8154.1GPT-6 Astra
Agentic workLike-for-likePublic boards, shown as published, kept out of the index152
Agentic work benchmarks for GPT-6 Astra and Grok 4.5
BenchmarkGPT-6 AstraGrok 4.5Leader
AA Agentic Index51.041.2GPT-6 Astra
Design Arena: agents building web apps13741218GPT-6 Astra
Design Arena: agents building full-stack apps13571249GPT-6 Astra
Design Arena: agents building mobile apps13121220GPT-6 Astra
Design Arena: agents building Android appsNot measured1236Only Grok 4.5 measured
Design Arena: agents building Godot games13481229GPT-6 Astra
Design Arena: agents building gamesNot measured1236Only Grok 4.5 measured
Design Arena: HTML slidesNot measured1155Only Grok 4.5 measured
Design Arena: PowerPoint slides12171209GPT-6 Astra
Design Arena: spreadsheets1378Not measuredOnly GPT-6 Astra measured
LiveBench research85.2%85.9%Grok 4.5
LiveBench browser84.0%44.0%GPT-6 Astra
LiveBench long agentic82.4%27.9%GPT-6 Astra
SREBench (Vals AI)56.9%0.8%GPT-6 Astra
Finance Agent (Vals AI)53.5%48.4%GPT-6 Astra
Tax Agent Bench (Vals AI)20.7%24.9%Grok 4.5
Legal Research Bench (Vals AI)39.4%38.0%GPT-6 Astra
Harvey's Legal Agent Benchmark (Vals AI)7.1%Not measuredOnly GPT-6 Astra measured
Excel Modeling Benchmark (Vals AI)71.7%52.9%GPT-6 Astra
BioMysteryBench (Vals AI)79.3%Not measuredOnly GPT-6 Astra measured
Terminal-Bench-Science (Vals AI)62.9%Not measuredOnly GPT-6 Astra measured
Vals Science Index65.1%Not measuredOnly GPT-6 Astra measured
Time Horizon Index (Vals AI)90.5%6.3%GPT-6 Astra
CUA-bench (Vals AI)19.2%Not measuredOnly GPT-6 Astra measured
Robo-bench (Vals AI)23.3%Not measuredOnly GPT-6 Astra measured
APEX-Agents64.7%56.2%GPT-6 Astra
Remote Labor Index20.8%Not measuredOnly GPT-6 Astra measured
BALROG68.3%Not measuredOnly GPT-6 Astra measured
PostTrainBenchNot measured23.4%Only Grok 4.5 measured
SpireClimb25.7%Not measuredOnly GPT-6 Astra measured
Vending-Bench 2$15,515$3,887GPT-6 Astra
LMArena SearchNot measured1216Only Grok 4.5 measured
Neither model has a result on the other 10 boards here
ReasoningLike-for-likePublic boards, shown as published, kept out of the index111
Reasoning benchmarks for GPT-6 Astra and Grok 4.5
BenchmarkGPT-6 AstraGrok 4.5Leader
GPQA DiamondNot measured92.9%Only Grok 4.5 measured
LiveBench reasoning92.7%87.2%GPT-6 Astra
MysteryMechanism (Vals AI)53.1%Not measuredOnly GPT-6 Astra measured
MMMU Pro (Vals AI)Not measured61.8%Only Grok 4.5 measured
GPQA Diamond (Artificial Analysis run)96.3%93.1%GPT-6 Astra
Humanity's Last Exam (Artificial Analysis run)54.7%42.7%GPT-6 Astra
GPQA Diamond (Epoch AI run)95.8%93.4%GPT-6 Astra
ARC-AGI98.5%87.2%GPT-6 Astra
ARC-AGI-295.0%52.6%GPT-6 Astra
SimpleBenchNot measured70.0%Only Grok 4.5 measured
Chess puzzles74.0%35.0%GPT-6 Astra
Mystery game puzzles84.0%Not measuredOnly GPT-6 Astra measured
EBR-bench76.2%Not measuredOnly GPT-6 Astra measured
LMArena Text: hard prompts14631462GPT-6 Astra
LMArena Text: expert14891465GPT-6 Astra
LMArena Text: hard prompts in English14641464GPT-6 Astra
LMArena Vision: diagrams12971304Grok 4.5
LMArena Vision: homework13371295GPT-6 Astra
Kagi LLM BenchmarkNot measured83.5%Only Grok 4.5 measured
Humanity's Last Exam (Scale run)60.6%Not measuredOnly GPT-6 Astra measured
Neither model has a result on the other 3 boards here
MathLike-for-likePublic boards, shown as published, kept out of the index70
Math benchmarks for GPT-6 Astra and Grok 4.5
BenchmarkGPT-6 AstraGrok 4.5Leader
OTIS Mock AIME100.0%97.8%GPT-6 Astra
FrontierMath, tiers 1 to 393.7%57.2%GPT-6 Astra
FrontierMath, tier 497.6%24.4%GPT-6 Astra
ProofBench99.0%31.0%GPT-6 Astra
LMArena Text: math14651460GPT-6 Astra
LMArena Text: mathematical work14841482GPT-6 Astra
MathArena81.9%34.1%GPT-6 Astra
Neither model has a result on the other 7 boards here
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index34
Knowledge benchmarks for GPT-6 Astra and Grok 4.5
BenchmarkGPT-6 AstraGrok 4.5Leader
MMLU ProNot measured89.2%Only Grok 4.5 measured
LegalBench (Vals AI)Not measured86.0%Only Grok 4.5 measured
CorpFin (Vals AI)Not measured67.4%Only Grok 4.5 measured
TaxEval (Vals AI)Not measured71.7%Only Grok 4.5 measured
MortgageTax (Vals AI)Not measured61.8%Only Grok 4.5 measured
MedCode (Vals AI)48.5%43.3%GPT-6 Astra
SimpleQA Verified75.6%48.3%GPT-6 Astra
LMArena Text: science14511464Grok 4.5
LMArena Text: medicine and healthcare14251440Grok 4.5
LMArena Text: legal and government14621463Grok 4.5
LMArena Text: business and finance14391441Grok 4.5
FACTS Benchmark Suite75.7%50.2%GPT-6 Astra
PRBench Finance47.5%Not measuredOnly GPT-6 Astra measured
PRBench Legal48.4%Not measuredOnly GPT-6 Astra measured
Neither model has a result on the other 6 boards here
Web designLike-for-likePublic boards, shown as published, kept out of the index90
Web design benchmarks for GPT-6 Astra and Grok 4.5
BenchmarkGPT-6 AstraGrok 4.5Leader
Design Arena: websites13361281GPT-6 Astra
Design Arena: UI components13941277GPT-6 Astra
Design Arena: game dev14801263GPT-6 Astra
Design Arena: data viz13341266GPT-6 Astra
Design Arena: 3D15001257GPT-6 Astra
Design Arena: all code categories13791275GPT-6 Astra
Design Arena: SVG14301214GPT-6 Astra
Design Arena: ASCII art13531257GPT-6 Astra
LiveBench design82.0%78.1%GPT-6 Astra
GeneralLike-for-likePublic boards, shown as published, kept out of the index1118
General benchmarks for GPT-6 Astra and Grok 4.5
BenchmarkGPT-6 AstraGrok 4.5Leader
Vals Index65.0%Not measuredOnly GPT-6 Astra measured
LiveBench data analysis83.0%73.0%GPT-6 Astra
SAGE (Vals AI)46.4%35.0%GPT-6 Astra
MedScribe (Vals AI)87.9%86.9%GPT-6 Astra
Vals Multimodal IndexNot measured63.4%Only Grok 4.5 measured
Long context reasoning (AA-LCR)80.7%79.3%GPT-6 Astra
DTBench97.3%96.5%GPT-6 Astra
LMCA64.4%45.2%GPT-6 Astra
Surface Evolver BenchNot measured74.4%Only Grok 4.5 measured
Furniture assembly80.0%22.5%GPT-6 Astra
LMArena Text14411448Grok 4.5
LMArena Text: instruction following14551445GPT-6 Astra
LMArena Text: creative writing14201442Grok 4.5
LMArena Vision12801287Grok 4.5
LMArena Text: English14471453Grok 4.5
LMArena Text: non-English14321440Grok 4.5
LMArena Text: Chinese14891495Grok 4.5
LMArena Text: German14591448GPT-6 Astra
LMArena Text: Japanese14051430Grok 4.5
LMArena Text: Korean14281406GPT-6 Astra
LMArena Text: French14321457Grok 4.5
LMArena Text: Spanish14221451Grok 4.5
LMArena Text: Russian14381449Grok 4.5
LMArena Text: Polish14221432Grok 4.5
LMArena Text: multi-turn14471456Grok 4.5
LMArena Text: longer queries14601462Grok 4.5
LMArena Text: writing and language14371445Grok 4.5
LMArena Text: entertainment and media14271434Grok 4.5
LMArena Vision: English12801285Grok 4.5
LMArena Vision: Chinese13611345GPT-6 Astra
LMArena Vision: reading text12921293Grok 4.5
LMArena Vision: humorNot measured1276Only Grok 4.5 measured
LMArena Vision: creative writing12861293Grok 4.5
LMArena DocumentNot measured1452Only Grok 4.5 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-6 Astra and Grok 4.5
BenchmarkGPT-6 AstraGrok 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-6 Astra$0.035Fits in one request
Grok 4.5$0.0050Fits in one request

Grok 4.5 costs less

Repository review

50K input + 3K output tokens

GPT-6 Astra$0.650Fits in one request
Grok 4.5$0.118Fits in one request

Grok 4.5 costs less

Agent loop

200K input + 10K output tokens

GPT-6 Astra$2.50Fits in one request
Grok 4.5$0.460Fits in one request

Grok 4.5 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-6 Astra and Grok 4.5
SpecificationOpenAI GPT-6 AstraSpaceXAI Grok 4.5
MakerOpenAIxAI
WeightsNo public weights listedNo public weights listed
ReleasedSeptember 4, 2026July 8, 2026
Context window1.05M500K
Input $/Mtok$10.00$2.00
Output $/Mtok$50.00$6.00
Coding index85.158.6
Independent measurements behind it56
Cost per solved taskNot computable$0.62
SourceOpenRouter listingOpenRouter listing

Questions

Is GPT-6 Astra better than Grok 4.5 for coding?

Pick GPT-6 Astra for coding: it scores 85.1 on the Vibe Coding Index against 58.6 for Grok 4.5, though on 5 benchmarks against 6. Pick Grok 4.5 for output tokens 8.3x cheaper ($6.00 vs $50.00 per million) and work measured by LiveBench coding or CyberBench (Vals AI), where it leads.

Which is cheaper, GPT-6 Astra or Grok 4.5?

GPT-6 Astra costs $10.00 per million input tokens and $50.00 per million output tokens; Grok 4.5 costs $2.00 and $6.00. Cost per solved task is known for Grok 4.5 only.

Which has the bigger context window, GPT-6 Astra or Grok 4.5?

GPT-6 Astra, with 1.05M tokens against 500K.

How many benchmarks is the GPT-6 Astra vs Grok 4.5 comparison based on?

103 benchmarks have a result for both models as of October 22, 2026. GPT-6 Astra's coding index rests on 5 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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