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Grok 4.3 vs o3

Grok 4.3 leads o3 on the Artificial Analysis Intelligence Index, 24.9 to 20.2, and Grok 4.3 costs 3.2x less per output token ($2.50 vs $8.00 per million). Updated October 22, 2026; 69 benchmarks have a result for both.

Replace Grok 4.3 Replace o3
Grok 4.3xAI
Coding
37.4
Overall
53.1
Output $/M
$2.50
36
o3OpenAI
Coding
No data
Overall
51.1
Output $/M
$8.00
33
vs boards won of 69 shared

Grok 4.3 or o3: which to pick

Only Grok 4.3 has a coding score, 37.4 on the Vibe Coding Index; o3 has none, so the two cannot be ranked on coding.

Pick o3 for work measured by WeirdML or Chess puzzles, where it leads.

Model AGrok 4.3xAI37.4/1003 independent benchmarks$0.31 per solved taskModel Bo3OpenAINot benchmarkedNo coding benchmark$0.571 per solved task
Shared results
69
Grok 4.3 only
36
o3 only
33
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
Grok 4.3 37.4 from 3 benchmarks, o3 not benchmarked.
Widest category
Agentic work, 17.0 points apart on average over 1 shared benchmark.
Widest single gap
SAGE (Vals AI): Grok 4.3 19.7% against o3 41.8%, 22.0 points apart on a 0 to 100 scale.
Output price
Grok 4.3 $2.50 against o3 $8.00 per million output tokens, 3.2x apart.
Context window
Grok 4.3 takes 1M tokens, o3 200K.

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
CategoryGrok 4.3Barso3Ties
Coding51
Intelligence10
Agentic work10
Reasoning74
Math22
Knowledge38
Web design41
General1317
All shared boards3633
CodingLike-for-likeSix of these boards feed the Vibe Coding Index51
Coding benchmarks for Grok 4.3 and o3
BenchmarkGrok 4.3o3Leader
Aider polyglotNot measured81.3%Only o3 measured
SWE-bench VerifiedNot measured58.4%Only o3 measured
SWE-bench MultimodalNot measured36.0%Only o3 measured
LMArena WebDev1358Not measuredOnly Grok 4.3 measured
AA Coding Index42.2Not measuredOnly Grok 4.3 measured
LiveCodeBench (Vals AI)84.5%83.9%Grok 4.3
SWE-bench Verified (Vals AI)71.4%Not measuredOnly Grok 4.3 measured
Vibe Code Bench (Vals AI)19.4%Not measuredOnly Grok 4.3 measured
Code migration (Vals AI)6.8%Not measuredOnly Grok 4.3 measured
ProgramBench (Vals AI)0.0%Not measuredOnly Grok 4.3 measured
Terminal-Bench 2.1 (Vals AI)42.0%Not measuredOnly Grok 4.3 measured
SkillsBench (Vals AI)40.6%Not measuredOnly Grok 4.3 measured
LiveCodeBench (Artificial Analysis run)Not measured80.8%Only o3 measured
SciCode48.3%Not measuredOnly Grok 4.3 measured
Terminal-Bench Hard (Artificial Analysis run)37.9%37.1%Grok 4.3
GSO-BenchNot measured8.8%Only o3 measured
WeirdML49.9%52.4%o3
ALE-Bench944.2933.5Grok 4.3
LMArena Text: coding14151407Grok 4.3
LMArena Text: software and IT14161415Grok 4.3
LMArena WebDev: React1353Not measuredOnly Grok 4.3 measured
LMArena WebDev: HTML1367Not measuredOnly Grok 4.3 measured
LMArena WebDev: from an image1375Not measuredOnly Grok 4.3 measured
SciCodeNot measured9.2%Only o3 measured
Neither model has a result on the other 15 boards here
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index10
Intelligence benchmarks for Grok 4.3 and o3
BenchmarkGrok 4.3o3Leader
AA Intelligence Index24.920.2Grok 4.3
Epoch Capabilities IndexNot measured146.7Only o3 measured
Agentic workLike-for-likePublic boards, shown as published, kept out of the index10
Agentic work benchmarks for Grok 4.3 and o3
BenchmarkGrok 4.3o3Leader
AA Agentic Index15.5Not measuredOnly Grok 4.3 measured
Design Arena: agents building web apps1126Not measuredOnly Grok 4.3 measured
Design Arena: agents building full-stack apps1006Not measuredOnly Grok 4.3 measured
Design Arena: agents building mobile apps1058Not measuredOnly Grok 4.3 measured
Design Arena: agents building Android apps962Not measuredOnly Grok 4.3 measured
Design Arena: agents building Godot games914Not measuredOnly Grok 4.3 measured
Design Arena: agents building games1007Not measuredOnly Grok 4.3 measured
Design Arena: HTML slides959Not measuredOnly Grok 4.3 measured
Design Arena: PowerPoint slides988Not measuredOnly Grok 4.3 measured
Design Arena: spreadsheets879Not measuredOnly Grok 4.3 measured
Finance Agent (Vals AI)37.7%Not measuredOnly Grok 4.3 measured
Tax Agent Bench (Vals AI)6.2%Not measuredOnly Grok 4.3 measured
Legal Research Bench (Vals AI)15.4%Not measuredOnly Grok 4.3 measured
Excel Modeling Benchmark (Vals AI)18.4%Not measuredOnly Grok 4.3 measured
τ²-Bench Telecom97.7%80.7%Grok 4.3
METR time horizonsNot measured65.4%Only o3 measured
GDPvalNot measured30.8%Only o3 measured
DeepResearch BenchNot measured45.2%Only o3 measured
OSWorldNot measured23.0%Only o3 measured
Vending-Bench 2$35Not measuredOnly Grok 4.3 measured
LMArena Search1166Not measuredOnly Grok 4.3 measured
Berkeley Function Calling Leaderboard (BFCL)Not measured63.0%Only o3 measured
BrowseComp-PlusNot measured65.9%Only o3 measured
Neither model has a result on the other 18 boards here
ReasoningLike-for-likePublic boards, shown as published, kept out of the index74
Reasoning benchmarks for Grok 4.3 and o3
BenchmarkGrok 4.3o3Leader
GPQA Diamond91.4%84.1%Grok 4.3
MMMU Pro (Vals AI)83.1%80.4%Grok 4.3
GPQA Diamond (Artificial Analysis run)90.1%82.7%Grok 4.3
Humanity's Last Exam (Artificial Analysis run)37.2%20.1%Grok 4.3
GPQA Diamond (Epoch AI run)88.8%81.8%Grok 4.3
ARC-AGINot measured60.8%Only o3 measured
ARC-AGI-2Not measured6.5%Only o3 measured
SimpleBenchNot measured53.1%Only o3 measured
Chess puzzles18.0%37.0%o3
Mystery game puzzlesNot measured29.0%Only o3 measured
VPCTNot measured52.0%Only o3 measured
LMArena Text: hard prompts13961402o3
LMArena Text: expert13841402o3
LMArena Text: hard prompts in English14021411o3
LMArena Vision: diagrams12411220Grok 4.3
LMArena Vision: homework12411234Grok 4.3
Kagi LLM BenchmarkNot measured67.6%Only o3 measured
Neither model has a result on the other 5 boards here
MathLike-for-likePublic boards, shown as published, kept out of the index22
Math benchmarks for Grok 4.3 and o3
BenchmarkGrok 4.3o3Leader
AIMENot measured85.3%Only o3 measured
MATH 500 (Vals AI)Not measured94.6%Only o3 measured
MGSM (Vals AI)Not measured91.8%Only o3 measured
AA Math IndexNot measured88.3Only o3 measured
AIME 2025 (Artificial Analysis run)Not measured88.3%Only o3 measured
OTIS Mock AIME93.3%84.4%Grok 4.3
FrontierMath, tiers 1 to 342.8%33.3%Grok 4.3
FrontierMath, tier 414.6%Not measuredOnly Grok 4.3 measured
ProofBench11.0%Not measuredOnly Grok 4.3 measured
MATH level 5Not measured97.8%Only o3 measured
LMArena Text: math13871426o3
LMArena Text: mathematical work13961423o3
Neither model has a result on the other 1 board here
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index38
Knowledge benchmarks for Grok 4.3 and o3
BenchmarkGrok 4.3o3Leader
MMLU Pro85.8%85.6%Grok 4.3
LegalBench (Vals AI)84.5%83.8%Grok 4.3
CaseLaw (Vals AI)79.3%Not measuredOnly Grok 4.3 measured
CorpFin (Vals AI)68.5%59.7%Grok 4.3
TaxEval (Vals AI)70.8%74.6%o3
MortgageTax (Vals AI)48.3%65.7%o3
MedQA (Vals AI)Not measured96.1%Only o3 measured
MedCode (Vals AI)38.1%47.3%o3
MMLU Pro (Artificial Analysis run)Not measured85.3%Only o3 measured
SimpleQA Verified33.2%49.4%o3
GeoBenchNot measured74.0%Only o3 measured
LMArena Text: science13991429o3
LMArena Text: medicine and healthcare13841448o3
LMArena Text: legal and government13861428o3
LMArena Text: business and finance13811393o3
FACTS Benchmark SuiteNot measured44.4%Only o3 measured
Neither model has a result on the other 2 boards here
Web designLike-for-likePublic boards, shown as published, kept out of the index41
Web design benchmarks for Grok 4.3 and o3
BenchmarkGrok 4.3o3Leader
Design Arena: websites11961036Grok 4.3
Design Arena: UI components11901017Grok 4.3
Design Arena: game dev11731034Grok 4.3
Design Arena: data viz11791200o3
Design Arena: 3D1124Not measuredOnly Grok 4.3 measured
Design Arena: all code categories11861020Grok 4.3
Design Arena: SVG1080Not measuredOnly Grok 4.3 measured
Design Arena: ASCII art1125Not measuredOnly Grok 4.3 measured
Neither model has a result on the other 1 board here
GeneralLike-for-likePublic boards, shown as published, kept out of the index1317
General benchmarks for Grok 4.3 and o3
BenchmarkGrok 4.3o3Leader
Public Benefits Bench (Vals AI)51.7%Not measuredOnly Grok 4.3 measured
SAGE (Vals AI)19.7%41.8%o3
MedScribe (Vals AI)74.4%76.7%o3
Vals Multimodal Index43.3%Not measuredOnly Grok 4.3 measured
IFBench83.3%71.4%Grok 4.3
Long context reasoning (AA-LCR)75.0%74.7%Grok 4.3
DTBench90.7%84.8%Grok 4.3
LMCA38.3%39.7%o3
Fiction.LiveBenchNot measured88.9%Only o3 measured
Creative writing (Lech Mazur)Not measured83.9%Only o3 measured
CL-benchNot measured17.8%Only o3 measured
LMArena Text13971410o3
LMArena Text: instruction following13661368o3
LMArena Text: creative writing13801359Grok 4.3
LMArena Vision12291214Grok 4.3
LMArena Text: English14041417o3
LMArena Text: non-English13851401o3
LMArena Text: Chinese14221437o3
LMArena Text: German13951420o3
LMArena Text: Japanese13791403o3
LMArena Text: Korean13541370o3
LMArena Text: French14111430o3
LMArena Text: Spanish13991395Grok 4.3
LMArena Text: Russian13991406o3
LMArena Text: Polish13981438o3
LMArena Text: multi-turn14061405Grok 4.3
LMArena Text: longer queries13931372Grok 4.3
LMArena Text: writing and language13851372Grok 4.3
LMArena Text: entertainment and media13701373o3
LMArena Vision: English12351221Grok 4.3
LMArena Vision: Chinese12571237Grok 4.3
LMArena Vision: reading text12351218Grok 4.3
LMArena Vision: humor12221222o3
LMArena Vision: captioningNot measured1210Only o3 measured
LMArena Vision: recognizing things12171234o3
LMArena Vision: creative writing12371201Grok 4.3
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 Grok 4.3 and o3
BenchmarkGrok 4.3o3Leader
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

Grok 4.3$0.0025Fits in one request
o3$0.0060Fits in one request

Grok 4.3 costs less

Repository review

50K input + 3K output tokens

Grok 4.3$0.070Fits in one request
o3$0.124Fits in one request

Grok 4.3 costs less

Agent loop

200K input + 10K output tokens

Grok 4.3$0.275Fits in one request
o3$0.480Exceeds the context window

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 Grok 4.3 and o3
SpecificationSpaceXAI Grok 4.3OpenAI o3
MakerxAIOpenAI
WeightsNo public weights listedNo public weights listed
ReleasedApril 30, 2026April 16, 2025
Context window1M200K
Input $/Mtok$1.25$2.00
Output $/Mtok$2.50$8.00
Coding index37.4Not benchmarked
Independent measurements behind it30
Cost per solved task$0.31$0.571
SourceOpenRouter listingOpenRouter listing

Questions

Is Grok 4.3 better than o3 for coding?

Only Grok 4.3 has a coding score, 37.4 on the Vibe Coding Index; o3 has none, so the two cannot be ranked on coding. Pick o3 for work measured by WeirdML or Chess puzzles, where it leads.

Which is cheaper, Grok 4.3 or o3?

Grok 4.3 costs $1.25 per million input tokens and $2.50 per million output tokens; o3 costs $2.00 and $8.00. Per solved SWE-bench Verified task, Grok 4.3 costs $0.31 and o3 $0.571.

Which has the bigger context window, Grok 4.3 or o3?

Grok 4.3, with 1M tokens against 200K.

How many benchmarks is the Grok 4.3 vs o3 comparison based on?

69 benchmarks have a result for both models as of October 22, 2026. Grok 4.3's coding index rests on 3 independent benchmarks and o3's on 0. Where only one model has a result, the page says so instead of naming a winner.

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