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Claude Sonnet 4.6 vs Gemini 3.5 Flash

Claude Sonnet 4.6 leads Gemini 3.5 Flash on coding, 57.3 to 39.8 on the Vibe Coding Index, and Gemini 3.5 Flash costs 1.7x less per output token ($9.00 vs $15.00 per million). Updated October 21, 2026; 99 benchmarks have a result for both.

Replace Claude Sonnet 4.6 Replace Gemini 3.5 Flash
Claude Sonnet 4.6Anthropic
Coding
57.3
Overall
60.3
Output $/M
$15.00
30
Gemini 3.5 FlashGoogle
Coding
39.8
Overall
63.8
Output $/M
$9.00
69
vs boards won of 99 shared

Claude Sonnet 4.6 or Gemini 3.5 Flash: which to pick

Pick Claude Sonnet 4.6 for coding: it scores 57.3 on the Vibe Coding Index against 39.8 for Gemini 3.5 Flash.

Pick Gemini 3.5 Flash for output tokens 1.7x cheaper ($9.00 vs $15.00 per million) and a lower cost per solved task ($1.21 against $1.68).

Model AClaude Sonnet 4.6Anthropic57.3/1005 independent benchmarks$1.68 per solved taskModel BGemini 3.5 FlashGoogle39.8/1004 independent benchmarks$1.21 per solved task
Shared results
99
Claude Sonnet 4.6 only
19
Gemini 3.5 Flash only
13
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
Claude Sonnet 4.6 57.3 from 5 benchmarks, Gemini 3.5 Flash 39.8 from 4 benchmarks.
Widest category
Math, 8.2 points apart on average over 4 shared benchmarks.
Widest single gap
SimpleQA Verified: Claude Sonnet 4.6 35.5% against Gemini 3.5 Flash 66.2%, 30.7 points apart on a 0 to 100 scale.
Output price
Claude Sonnet 4.6 $15.00 against Gemini 3.5 Flash $9.00 per million output tokens, 1.7x apart.
Context window
Claude Sonnet 4.6 takes 1M tokens, Gemini 3.5 Flash 1.05M.

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
CategoryClaude Sonnet 4.6BarsGemini 3.5 FlashTies
Coding106
Intelligence02
Agentic work85
Reasoning212
Math13
Knowledge29
Web design35
General427
All shared boards3069
CodingLike-for-likeSix of these boards feed the Vibe Coding Index106
Coding benchmarks for Claude Sonnet 4.6 and Gemini 3.5 Flash
BenchmarkClaude Sonnet 4.6Gemini 3.5 FlashLeader
LiveBench coding66.6%Not measuredOnly Claude Sonnet 4.6 measured
LMArena WebDev15231499Claude Sonnet 4.6
AA Coding Index63.0Not measuredOnly Claude Sonnet 4.6 measured
LiveCodeBench (Vals AI)82.1%87.6%Gemini 3.5 Flash
SWE-bench Verified (Vals AI)77.4%78.8%Gemini 3.5 Flash
Terminal-Bench 4 (Vals AI)Not measured6.1%Only Gemini 3.5 Flash measured
Vibe Code Bench (Vals AI)55.8%48.7%Claude Sonnet 4.6
Code migration (Vals AI)39.9%26.8%Claude Sonnet 4.6
ProgramBench (Vals AI)0.5%0.0%Claude Sonnet 4.6
Terminal-Bench 2.1 (Vals AI)57.3%74.2%Gemini 3.5 Flash
SkillsBench (Vals AI)49.0%52.7%Gemini 3.5 Flash
SciCode50.1%53.9%Gemini 3.5 Flash
Terminal-Bench Hard (Artificial Analysis run)53.0%46.2%Claude Sonnet 4.6
Terminal-Bench53.4%Not measuredOnly Claude Sonnet 4.6 measured
FrontierCode24.3%Not measuredOnly Claude Sonnet 4.6 measured
WeirdML66.1%62.6%Claude Sonnet 4.6
ALE-BenchNot measured911.0Only Gemini 3.5 Flash measured
LMArena Text: coding15031493Claude Sonnet 4.6
LMArena Text: software and IT14911494Gemini 3.5 Flash
LMArena WebDev: React15121495Claude Sonnet 4.6
LMArena WebDev: HTML15271522Claude Sonnet 4.6
LMArena WebDev: from an image15291504Claude Sonnet 4.6
SciCodeNot measured12.3%Only Gemini 3.5 Flash measured
Neither model has a result on the other 16 boards here
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index02
Intelligence benchmarks for Claude Sonnet 4.6 and Gemini 3.5 Flash
BenchmarkClaude Sonnet 4.6Gemini 3.5 FlashLeader
AA Intelligence Index30.133.6Gemini 3.5 Flash
Epoch Capabilities Index152.8154.9Gemini 3.5 Flash
Agentic workLike-for-likePublic boards, shown as published, kept out of the index85
Agentic work benchmarks for Claude Sonnet 4.6 and Gemini 3.5 Flash
BenchmarkClaude Sonnet 4.6Gemini 3.5 FlashLeader
AA Agentic Index31.8Not measuredOnly Claude Sonnet 4.6 measured
Design Arena: agents building web apps11901202Gemini 3.5 Flash
Design Arena: agents building full-stack apps12131197Claude Sonnet 4.6
Design Arena: agents building mobile apps12121174Claude Sonnet 4.6
Design Arena: agents building Android apps11961184Claude Sonnet 4.6
Design Arena: agents building Godot games12261098Claude Sonnet 4.6
Design Arena: agents building games11771180Gemini 3.5 Flash
Design Arena: HTML slidesNot measured1142Only Gemini 3.5 Flash measured
Design Arena: PowerPoint slidesNot measured1179Only Gemini 3.5 Flash measured
LiveBench research63.6%Not measuredOnly Claude Sonnet 4.6 measured
LiveBench browser68.0%Not measuredOnly Claude Sonnet 4.6 measured
LiveBench long agentic23.1%Not measuredOnly Claude Sonnet 4.6 measured
Finance Agent (Vals AI)51.0%57.9%Gemini 3.5 Flash
Tax Agent Bench (Vals AI)25.8%21.6%Claude Sonnet 4.6
Legal Research Bench (Vals AI)38.5%30.8%Claude Sonnet 4.6
Excel Modeling Benchmark (Vals AI)60.2%63.5%Gemini 3.5 Flash
Terminal-Bench-Science (Vals AI)Not measured5.7%Only Gemini 3.5 Flash measured
τ²-Bench Telecom79.5%95.6%Gemini 3.5 Flash
APEX-Agents43.0%27.5%Claude Sonnet 4.6
OSWorld 2.09.3%Not measuredOnly Claude Sonnet 4.6 measured
DeepResearch Bench54.9%Not measuredOnly Claude Sonnet 4.6 measured
OSWorld72.1%Not measuredOnly Claude Sonnet 4.6 measured
Vending-Bench 2$7,204$5,396Claude Sonnet 4.6
Neither model has a result on the other 18 boards here
ReasoningLike-for-likePublic boards, shown as published, kept out of the index212
Reasoning benchmarks for Claude Sonnet 4.6 and Gemini 3.5 Flash
BenchmarkClaude Sonnet 4.6Gemini 3.5 FlashLeader
GPQA Diamond85.6%92.7%Gemini 3.5 Flash
LiveBench reasoning86.4%Not measuredOnly Claude Sonnet 4.6 measured
MMMU Pro (Vals AI)83.6%88.3%Gemini 3.5 Flash
GPQA Diamond (Artificial Analysis run)87.5%92.2%Gemini 3.5 Flash
Humanity's Last Exam (Artificial Analysis run)33.6%42.7%Gemini 3.5 Flash
GPQA Diamond (Epoch AI run)87.4%92.8%Gemini 3.5 Flash
ARC-AGI86.5%92.5%Gemini 3.5 Flash
ARC-AGI-260.4%72.1%Gemini 3.5 Flash
SimpleBenchNot measured76.7%Only Gemini 3.5 Flash measured
Chess puzzles23.0%45.0%Gemini 3.5 Flash
Mystery game puzzles16.0%32.0%Gemini 3.5 Flash
EBR-benchNot measured4.8%Only Gemini 3.5 Flash measured
LMArena Text: hard prompts14851488Gemini 3.5 Flash
LMArena Text: expert15001495Claude Sonnet 4.6
LMArena Text: hard prompts in English14931483Claude Sonnet 4.6
LMArena Vision: diagrams13061323Gemini 3.5 Flash
LMArena Vision: homework13111330Gemini 3.5 Flash
Neither model has a result on the other 5 boards here
MathLike-for-likePublic boards, shown as published, kept out of the index13
Math benchmarks for Claude Sonnet 4.6 and Gemini 3.5 Flash
BenchmarkClaude Sonnet 4.6Gemini 3.5 FlashLeader
AIME92.3%Not measuredOnly Claude Sonnet 4.6 measured
OTIS Mock AIME85.8%95.6%Gemini 3.5 Flash
FrontierMath, tiers 1 to 3Not measured62.8%Only Gemini 3.5 Flash measured
FrontierMath, tier 4Not measured26.8%Only Gemini 3.5 Flash measured
ProofBench45.0%31.0%Claude Sonnet 4.6
LMArena Text: math14621504Gemini 3.5 Flash
LMArena Text: mathematical work14831495Gemini 3.5 Flash
Neither model has a result on the other 6 boards here
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index29
Knowledge benchmarks for Claude Sonnet 4.6 and Gemini 3.5 Flash
BenchmarkClaude Sonnet 4.6Gemini 3.5 FlashLeader
MMLU Pro87.3%89.5%Gemini 3.5 Flash
LegalBench (Vals AI)82.1%83.6%Gemini 3.5 Flash
CaseLaw (Vals AI)64.0%Not measuredOnly Claude Sonnet 4.6 measured
CorpFin (Vals AI)65.3%64.7%Claude Sonnet 4.6
TaxEval (Vals AI)77.1%74.4%Claude Sonnet 4.6
MortgageTax (Vals AI)67.7%68.1%Gemini 3.5 Flash
MedQA (Vals AI)92.1%Not measuredOnly Claude Sonnet 4.6 measured
MedCode (Vals AI)Not measured55.8%Only Gemini 3.5 Flash measured
SimpleQA Verified35.5%66.2%Gemini 3.5 Flash
LMArena Text: science14741495Gemini 3.5 Flash
LMArena Text: medicine and healthcare14511483Gemini 3.5 Flash
LMArena Text: legal and government14701488Gemini 3.5 Flash
LMArena Text: business and finance14641467Gemini 3.5 Flash
FACTS Benchmark Suite37.0%63.1%Gemini 3.5 Flash
Neither model has a result on the other 4 boards here
Web designLike-for-likePublic boards, shown as published, kept out of the index35
Web design benchmarks for Claude Sonnet 4.6 and Gemini 3.5 Flash
BenchmarkClaude Sonnet 4.6Gemini 3.5 FlashLeader
Design Arena: websites12851268Claude Sonnet 4.6
Design Arena: UI components12721273Gemini 3.5 Flash
Design Arena: game dev12591263Gemini 3.5 Flash
Design Arena: data viz12771236Claude Sonnet 4.6
Design Arena: 3D12341244Gemini 3.5 Flash
Design Arena: all code categories12761266Claude Sonnet 4.6
Design Arena: SVG11971254Gemini 3.5 Flash
Design Arena: ASCII art12351254Gemini 3.5 Flash
LiveBench design71.8%Not measuredOnly Claude Sonnet 4.6 measured
GeneralLike-for-likePublic boards, shown as published, kept out of the index427
General benchmarks for Claude Sonnet 4.6 and Gemini 3.5 Flash
BenchmarkClaude Sonnet 4.6Gemini 3.5 FlashLeader
LiveBench data analysis76.1%Not measuredOnly Claude Sonnet 4.6 measured
Public Benefits Bench (Vals AI)62.5%59.5%Claude Sonnet 4.6
SAGE (Vals AI)46.6%49.9%Gemini 3.5 Flash
MedScribe (Vals AI)Not measured76.6%Only Gemini 3.5 Flash measured
Vals Multimodal Index60.6%62.9%Gemini 3.5 Flash
IFBench56.6%76.3%Gemini 3.5 Flash
Long context reasoning (AA-LCR)80.0%74.3%Claude Sonnet 4.6
DTBench89.9%94.7%Gemini 3.5 Flash
LMCA46.5%47.1%Gemini 3.5 Flash
Surface Evolver BenchNot measured58.1%Only Gemini 3.5 Flash measured
ExploitBench23.6%Not measuredOnly Claude Sonnet 4.6 measured
LMArena Text14581482Gemini 3.5 Flash
LMArena Text: instruction following14761467Claude Sonnet 4.6
LMArena Text: creative writing14351470Gemini 3.5 Flash
LMArena Vision12831308Gemini 3.5 Flash
LMArena Text: English14721481Gemini 3.5 Flash
LMArena Text: non-English14401475Gemini 3.5 Flash
LMArena Text: Chinese14911527Gemini 3.5 Flash
LMArena Text: German14281494Gemini 3.5 Flash
LMArena Text: Japanese14201486Gemini 3.5 Flash
LMArena Text: Korean14101448Gemini 3.5 Flash
LMArena Text: French14651490Gemini 3.5 Flash
LMArena Text: Spanish14641480Gemini 3.5 Flash
LMArena Text: Russian14401493Gemini 3.5 Flash
LMArena Text: Polish14431516Gemini 3.5 Flash
LMArena Text: multi-turn14641481Gemini 3.5 Flash
LMArena Text: longer queries14791483Gemini 3.5 Flash
LMArena Text: writing and language14441478Gemini 3.5 Flash
LMArena Text: entertainment and media14311459Gemini 3.5 Flash
LMArena Vision: English12981305Gemini 3.5 Flash
LMArena Vision: Chinese13071377Gemini 3.5 Flash
LMArena Vision: reading text12961317Gemini 3.5 Flash
LMArena Vision: humor12481321Gemini 3.5 Flash
LMArena Vision: recognizing things1195Not measuredOnly Claude Sonnet 4.6 measured
LMArena Vision: creative writing12721301Gemini 3.5 Flash
LMArena Document14821463Claude Sonnet 4.6
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 Claude Sonnet 4.6 and Gemini 3.5 Flash
BenchmarkClaude Sonnet 4.6Gemini 3.5 FlashLeader
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

Claude Sonnet 4.6$0.011Fits in one request
Gemini 3.5 Flash$0.0060Fits in one request

Gemini 3.5 Flash costs less

Repository review

50K input + 3K output tokens

Claude Sonnet 4.6$0.195Fits in one request
Gemini 3.5 Flash$0.102Fits in one request

Gemini 3.5 Flash costs less

Agent loop

200K input + 10K output tokens

Claude Sonnet 4.6$0.750Fits in one request
Gemini 3.5 Flash$0.390Fits in one request

Gemini 3.5 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 Claude Sonnet 4.6 and Gemini 3.5 Flash
SpecificationAnthropic Claude Sonnet 4.6Google Gemini 3.5 Flash
MakerAnthropicGoogle
WeightsNo public weights listedNo public weights listed
ReleasedFebruary 17, 2026May 19, 2026
Context window1M1.05M
Input $/Mtok$3.00$1.50
Output $/Mtok$15.00$9.00
Coding index57.339.8
Independent measurements behind it54
Cost per solved task$1.68$1.21
SourceOpenRouter listingOpenRouter listing

Questions

Is Claude Sonnet 4.6 better than Gemini 3.5 Flash for coding?

Pick Claude Sonnet 4.6 for coding: it scores 57.3 on the Vibe Coding Index against 39.8 for Gemini 3.5 Flash. Pick Gemini 3.5 Flash for output tokens 1.7x cheaper ($9.00 vs $15.00 per million) and a lower cost per solved task ($1.21 against $1.68).

Which is cheaper, Claude Sonnet 4.6 or Gemini 3.5 Flash?

Claude Sonnet 4.6 costs $3.00 per million input tokens and $15.00 per million output tokens; Gemini 3.5 Flash costs $1.50 and $9.00. Per solved SWE-bench Verified task, Claude Sonnet 4.6 costs $1.68 and Gemini 3.5 Flash $1.21.

Which has the bigger context window, Claude Sonnet 4.6 or Gemini 3.5 Flash?

Gemini 3.5 Flash, with 1.05M tokens against 1M.

How many benchmarks is the Claude Sonnet 4.6 vs Gemini 3.5 Flash comparison based on?

99 benchmarks have a result for both models as of October 21, 2026. Claude Sonnet 4.6's coding index rests on 5 independent benchmarks and Gemini 3.5 Flash's on 4. 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/claude-sonnet-4-6-vs-gemini-3-5-flash">LLMBenchmark.ai, Claude Sonnet 4.6 vs Gemini 3.5 Flash</a></p>