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Gemini 3.8 Flash vs Grok 4.6

Grok 4.6 leads Gemini 3.8 Flash on coding, 65.7 to 61.6 on the Vibe Coding Index, and Gemini 3.8 Flash costs 1.6x less per output token ($3.75 vs $6.00 per million). Updated October 22, 2026; 117 benchmarks have a result for both.

Replace Gemini 3.8 Flash Replace Grok 4.6
Gemini 3.8 FlashGoogle
Coding
61.6
Overall
69.0
Output $/M
$3.75
75
Grok 4.6xAI
Coding
65.7
Overall
67.4
Output $/M
$6.00
40
vs boards won of 117 shared, 2 tied

Gemini 3.8 Flash or Grok 4.6: which to pick

Pick Grok 4.6 for coding: it scores 65.7 on the Vibe Coding Index against 61.6 for Gemini 3.8 Flash.

Pick Gemini 3.8 Flash for output tokens 1.6x cheaper ($3.75 vs $6.00 per million) and a larger context window (1.05M against 500K tokens).

Model AGemini 3.8 FlashGoogle61.6/1006 independent benchmarks$2.74 per solved taskModel BGrok 4.6xAI65.7/1006 independent benchmarks$0.82 per solved task
Shared results
117
Gemini 3.8 Flash only
11
Grok 4.6 only
6
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
Gemini 3.8 Flash 61.6 from 6 benchmarks, Grok 4.6 65.7 from 6 benchmarks.
Widest category
General, 10.1 points apart on average over 31 shared benchmarks.
Widest single gap
Design Arena: agents building Android apps: Gemini 3.8 Flash 1078 against Grok 4.6 1291, 26.6 points apart on a 0 to 100 scale.
Output price
Gemini 3.8 Flash $3.75 against Grok 4.6 $6.00 per million output tokens, 1.6x apart.
Context window
Gemini 3.8 Flash 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
CategoryGemini 3.8 FlashBarsGrok 4.6Ties
Coding12111 tie
Intelligence11
Agentic work4151 tie
Reasoning132
Math33
Knowledge100
Web design63
General265
All shared boards75402 ties
CodingLike-for-likeSix of these boards feed the Vibe Coding Index1211
Coding benchmarks for Gemini 3.8 Flash and Grok 4.6
BenchmarkGemini 3.8 FlashGrok 4.6Leader
LiveBench coding82.2%89.1%Grok 4.6
LMArena WebDev15851617Grok 4.6
AA Coding Index76.376.8Grok 4.6
LiveCodeBench (Vals AI)89.5%88.2%Gemini 3.8 Flash
SWE-bench Verified (Vals AI)80.0%95.6%Grok 4.6
Terminal-Bench 4 (Vals AI)19.7%17.2%Gemini 3.8 Flash
Vibe Code Bench (Vals AI)78.7%76.2%Gemini 3.8 Flash
Code migration (Vals AI)36.5%44.6%Grok 4.6
ProgramBench (Vals AI)1.0%1.0%Tie
IOI (Vals AI)56.9%47.6%Gemini 3.8 Flash
Terminal-Bench 2.1 (Vals AI)81.3%78.3%Gemini 3.8 Flash
SWE-bench Multimodal (Vals AI)40.8%Not measuredOnly Gemini 3.8 Flash measured
Vibe Code Bench 1-100 (Vals AI)18.8%14.8%Gemini 3.8 Flash
SkillsBench (Vals AI)58.0%55.8%Gemini 3.8 Flash
CyberBench (Vals AI)43.8%67.7%Grok 4.6
SciCode56.6%56.5%Gemini 3.8 Flash
FrontierCode41.2%48.0%Grok 4.6
FrontierSWE19.6%25.3%Grok 4.6
WeirdML84.8%67.3%Gemini 3.8 Flash
ALE-Bench1269.71508.1Grok 4.6
LMArena Text: coding15081466Gemini 3.8 Flash
LMArena Text: software and IT15071457Gemini 3.8 Flash
LMArena WebDev: React15771631Grok 4.6
LMArena WebDev: HTML16161597Gemini 3.8 Flash
LMArena WebDev: from an image15931603Grok 4.6
SciCode12.3%Not measuredOnly Gemini 3.8 Flash measured
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 Gemini 3.8 Flash and Grok 4.6
BenchmarkGemini 3.8 FlashGrok 4.6Leader
AA Intelligence Index40.944.3Grok 4.6
Epoch Capabilities Index157.4156.6Gemini 3.8 Flash
Agentic workLike-for-likePublic boards, shown as published, kept out of the index415
Agentic work benchmarks for Gemini 3.8 Flash and Grok 4.6
BenchmarkGemini 3.8 FlashGrok 4.6Leader
AA Agentic Index40.253.0Grok 4.6
Design Arena: agents building web apps12381248Grok 4.6
Design Arena: agents building full-stack apps12441264Grok 4.6
Design Arena: agents building mobile apps12361234Gemini 3.8 Flash
Design Arena: agents building Android apps10781291Grok 4.6
Design Arena: agents building Godot games12731276Grok 4.6
Design Arena: agents building gamesNot measured1209Only Grok 4.6 measured
Design Arena: HTML slidesNot measured1250Only Grok 4.6 measured
Design Arena: PowerPoint slides11531237Grok 4.6
Design Arena: spreadsheets1022Not measuredOnly Gemini 3.8 Flash measured
LiveBench research79.1%84.5%Grok 4.6
LiveBench browser64.0%64.0%Tie
LiveBench long agentic30.1%40.7%Grok 4.6
SREBench (Vals AI)11.1%Not measuredOnly Gemini 3.8 Flash measured
Finance Agent (Vals AI)61.4%53.7%Gemini 3.8 Flash
Tax Agent Bench (Vals AI)32.1%33.1%Grok 4.6
Legal Research Bench (Vals AI)38.9%48.1%Grok 4.6
Harvey's Legal Agent Benchmark (Vals AI)12.1%Not measuredOnly Gemini 3.8 Flash measured
Excel Modeling Benchmark (Vals AI)72.2%62.7%Gemini 3.8 Flash
BioMysteryBench (Vals AI)62.2%72.2%Grok 4.6
Terminal-Bench-Science (Vals AI)8.6%11.4%Grok 4.6
Vals Science Index35.8%38.1%Grok 4.6
Time Horizon Index (Vals AI)18.8%5.8%Gemini 3.8 Flash
CUA-bench (Vals AI)4.2%Not measuredOnly Gemini 3.8 Flash measured
APEX-Agents64.3%65.3%Grok 4.6
Remote Labor Index5.8%Not measuredOnly Gemini 3.8 Flash measured
Vending-Bench 2$5,094$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 index132
Reasoning benchmarks for Gemini 3.8 Flash and Grok 4.6
BenchmarkGemini 3.8 FlashGrok 4.6Leader
GPQA Diamond94.4%94.7%Grok 4.6
LiveBench reasoning89.3%91.2%Grok 4.6
MysteryMechanism (Vals AI)36.5%30.6%Gemini 3.8 Flash
MMMU Pro (Vals AI)89.1%Not measuredOnly Gemini 3.8 Flash measured
GPQA Diamond (Artificial Analysis run)95.3%94.9%Gemini 3.8 Flash
Humanity's Last Exam (Artificial Analysis run)47.8%44.1%Gemini 3.8 Flash
GPQA Diamond (Epoch AI run)95.4%94.0%Gemini 3.8 Flash
ARC-AGI98.5%87.5%Gemini 3.8 Flash
ARC-AGI-289.2%67.1%Gemini 3.8 Flash
SimpleBenchNot measured75.9%Only Grok 4.6 measured
Chess puzzles58.0%33.0%Gemini 3.8 Flash
Mystery game puzzles47.0%34.0%Gemini 3.8 Flash
EBR-benchNot measured30.5%Only Grok 4.6 measured
LMArena Text: hard prompts15091448Gemini 3.8 Flash
LMArena Text: expert15261469Gemini 3.8 Flash
LMArena Text: hard prompts in English15041445Gemini 3.8 Flash
LMArena Vision: diagrams13451285Gemini 3.8 Flash
LMArena Vision: homework13511283Gemini 3.8 Flash
Neither model has a result on the other 4 boards here
MathLike-for-likePublic boards, shown as published, kept out of the index33
Math benchmarks for Gemini 3.8 Flash and Grok 4.6
BenchmarkGemini 3.8 FlashGrok 4.6Leader
OTIS Mock AIME98.9%99.2%Grok 4.6
FrontierMath, tiers 1 to 368.4%66.0%Gemini 3.8 Flash
FrontierMath, tier 422.0%31.7%Grok 4.6
ProofBench48.0%51.0%Grok 4.6
LMArena Text: math15321417Gemini 3.8 Flash
LMArena Text: mathematical work15191464Gemini 3.8 Flash
Neither model has a result on the other 7 boards here
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index100
Knowledge benchmarks for Gemini 3.8 Flash and Grok 4.6
BenchmarkGemini 3.8 FlashGrok 4.6Leader
MMLU Pro90.2%89.4%Gemini 3.8 Flash
LegalBench (Vals AI)87.0%86.3%Gemini 3.8 Flash
CorpFin (Vals AI)Not measured66.2%Only Grok 4.6 measured
TaxEval (Vals AI)74.5%71.1%Gemini 3.8 Flash
MortgageTax (Vals AI)65.3%64.2%Gemini 3.8 Flash
MedCode (Vals AI)48.1%44.7%Gemini 3.8 Flash
SimpleQA Verified69.7%49.3%Gemini 3.8 Flash
LMArena Text: science15231437Gemini 3.8 Flash
LMArena Text: medicine and healthcare15081420Gemini 3.8 Flash
LMArena Text: legal and government14971429Gemini 3.8 Flash
LMArena Text: business and finance14791416Gemini 3.8 Flash
FACTS Benchmark Suite69.4%Not measuredOnly Gemini 3.8 Flash measured
Neither model has a result on the other 6 boards here
Web designLike-for-likePublic boards, shown as published, kept out of the index63
Web design benchmarks for Gemini 3.8 Flash and Grok 4.6
BenchmarkGemini 3.8 FlashGrok 4.6Leader
Design Arena: websites13001289Gemini 3.8 Flash
Design Arena: UI components13161294Gemini 3.8 Flash
Design Arena: game dev13041296Gemini 3.8 Flash
Design Arena: data viz12701282Grok 4.6
Design Arena: 3D12941277Gemini 3.8 Flash
Design Arena: all code categories13031292Gemini 3.8 Flash
Design Arena: SVG12961240Gemini 3.8 Flash
Design Arena: ASCII art12621279Grok 4.6
LiveBench design72.7%79.8%Grok 4.6
GeneralLike-for-likePublic boards, shown as published, kept out of the index265
General benchmarks for Gemini 3.8 Flash and Grok 4.6
BenchmarkGemini 3.8 FlashGrok 4.6Leader
Vals Index56.0%Not measuredOnly Gemini 3.8 Flash measured
LiveBench data analysis54.0%75.3%Grok 4.6
Public Benefits Bench (Vals AI)65.3%66.8%Grok 4.6
SAGE (Vals AI)35.1%28.9%Gemini 3.8 Flash
MedScribe (Vals AI)84.5%86.5%Grok 4.6
Long context reasoning (AA-LCR)84.0%81.0%Gemini 3.8 Flash
DTBench95.7%97.3%Grok 4.6
LMCA52.9%48.5%Gemini 3.8 Flash
Surface Evolver Bench76.9%Not measuredOnly Gemini 3.8 Flash measured
Furniture assembly31.7%40.0%Grok 4.6
LMArena Text14991429Gemini 3.8 Flash
LMArena Text: instruction following14921431Gemini 3.8 Flash
LMArena Text: creative writing14881426Gemini 3.8 Flash
LMArena Vision13151263Gemini 3.8 Flash
LMArena Text: English14981433Gemini 3.8 Flash
LMArena Text: non-English14911420Gemini 3.8 Flash
LMArena Text: Chinese15531476Gemini 3.8 Flash
LMArena Text: German15011426Gemini 3.8 Flash
LMArena Text: Japanese15071378Gemini 3.8 Flash
LMArena Text: Korean14641391Gemini 3.8 Flash
LMArena Text: French14961455Gemini 3.8 Flash
LMArena Text: Spanish14871414Gemini 3.8 Flash
LMArena Text: Russian15141421Gemini 3.8 Flash
LMArena Text: Polish14971430Gemini 3.8 Flash
LMArena Text: multi-turn15031425Gemini 3.8 Flash
LMArena Text: longer queries15071456Gemini 3.8 Flash
LMArena Text: writing and language14941429Gemini 3.8 Flash
LMArena Text: entertainment and media14801421Gemini 3.8 Flash
LMArena Vision: English13181270Gemini 3.8 Flash
LMArena Vision: Chinese14161289Gemini 3.8 Flash
LMArena Vision: reading text13331272Gemini 3.8 Flash
LMArena Vision: humor13211270Gemini 3.8 Flash
LMArena Vision: creative writing12991262Gemini 3.8 Flash
LMArena DocumentNot measured1452Only Grok 4.6 measured
Neither model has a result on the other 12 boards here
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
Image generation benchmarks for Gemini 3.8 Flash and Grok 4.6
BenchmarkGemini 3.8 FlashGrok 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

Gemini 3.8 Flash$0.0026Fits in one request
Grok 4.6$0.0050Fits in one request

Gemini 3.8 Flash costs less

Repository review

50K input + 3K output tokens

Gemini 3.8 Flash$0.049Fits in one request
Grok 4.6$0.118Fits in one request

Gemini 3.8 Flash costs less

Agent loop

200K input + 10K output tokens

Gemini 3.8 Flash$0.188Fits in one request
Grok 4.6$0.460Fits in one request

Gemini 3.8 Flash 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 Gemini 3.8 Flash and Grok 4.6
SpecificationGoogle Gemini 3.8 FlashSpaceXAI Grok 4.6
MakerGooglexAI
WeightsNo public weights listedNo public weights listed
ReleasedSeptember 2, 2026August 12, 2026
Context window1.05M500K
Input $/Mtok$0.75$2.00
Output $/Mtok$3.75$6.00
Coding index61.665.7
Independent measurements behind it66
Cost per solved task$2.74$0.82
SourceOpenRouter listingOpenRouter listing

Questions

Is Gemini 3.8 Flash better than Grok 4.6 for coding?

Pick Grok 4.6 for coding: it scores 65.7 on the Vibe Coding Index against 61.6 for Gemini 3.8 Flash. Pick Gemini 3.8 Flash for output tokens 1.6x cheaper ($3.75 vs $6.00 per million) and a larger context window (1.05M against 500K tokens).

Which is cheaper, Gemini 3.8 Flash or Grok 4.6?

Gemini 3.8 Flash costs $0.75 per million input tokens and $3.75 per million output tokens; Grok 4.6 costs $2.00 and $6.00. Per solved SWE-bench Verified task, Gemini 3.8 Flash costs $2.74 and Grok 4.6 $0.82.

Which has the bigger context window, Gemini 3.8 Flash or Grok 4.6?

Gemini 3.8 Flash, with 1.05M tokens against 500K.

How many benchmarks is the Gemini 3.8 Flash vs Grok 4.6 comparison based on?

117 benchmarks have a result for both models as of October 22, 2026. Gemini 3.8 Flash's coding index rests on 6 independent benchmarks and Grok 4.6's on 6. Where only one model has a result, the page says so instead of naming a winner.

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<p style="font:13px/1.4 sans-serif;margin:6px 0 0">Source: <a href="https://llmbenchmark.ai/compare/gemini-3-8-flash-vs-grok-4-6">LLMBenchmark.ai, Gemini 3.8 Flash vs Grok 4.6</a></p>