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Claude Sonnet 5 vs Gemini 3.5 Flash

Claude Sonnet 5 leads Gemini 3.5 Flash on coding, 57.7 to 39.8 on the Vibe Coding Index, at about the same output price ($10.00 vs $9.00 per million). Updated October 21, 2026; 105 benchmarks have a result for both.

Replace Claude Sonnet 5 Replace Gemini 3.5 Flash
Claude Sonnet 5Anthropic
Coding
57.7
Overall
63.2
Output $/M
$10.00
47
Gemini 3.5 FlashGoogle
Coding
39.8
Overall
63.8
Output $/M
$9.00
55
vs boards won of 105 shared, 3 tied

Claude Sonnet 5 or Gemini 3.5 Flash: which to pick

Pick Claude Sonnet 5 for coding: it scores 57.7 on the Vibe Coding Index against 39.8 for Gemini 3.5 Flash.

Pick Gemini 3.5 Flash for output tokens 1.1x cheaper ($9.00 vs $10.00 per million) and a lower cost per solved task ($1.21 against $1.87).

Model AClaude Sonnet 5Anthropic57.7/1006 independent benchmarks$1.87 per solved taskModel BGemini 3.5 FlashGoogle39.8/1004 independent benchmarks$1.21 per solved task
Shared results
105
Claude Sonnet 5 only
16
Gemini 3.5 Flash only
7
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 5 57.7 from 6 benchmarks, Gemini 3.5 Flash 39.8 from 4 benchmarks.
Widest category
Math, 10.1 points apart on average over 6 shared benchmarks.
Widest single gap
ProofBench: Claude Sonnet 5 77.0% against Gemini 3.5 Flash 31.0%, 46.0 points apart on a 0 to 100 scale.
Output price
Claude Sonnet 5 $10.00 against Gemini 3.5 Flash $9.00 per million output tokens, 1.1x apart.
Context window
Claude Sonnet 5 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 5BarsGemini 3.5 FlashTies
Coding1251 tie
Intelligence20
Agentic work1311 tie
Reasoning1111 tie
Math33
Knowledge47
Web design62
General626
All shared boards47553 ties
CodingLike-for-likeSix of these boards feed the Vibe Coding Index125
Coding benchmarks for Claude Sonnet 5 and Gemini 3.5 Flash
BenchmarkClaude Sonnet 5Gemini 3.5 FlashLeader
LiveBench coding74.7%Not measuredOnly Claude Sonnet 5 measured
LMArena WebDev15401499Claude Sonnet 5
AA Coding Index71.5Not measuredOnly Claude Sonnet 5 measured
LiveCodeBench (Vals AI)82.4%87.6%Gemini 3.5 Flash
SWE-bench Verified (Vals AI)79.6%78.8%Claude Sonnet 5
Terminal-Bench 4 (Vals AI)10.6%6.1%Claude Sonnet 5
Vibe Code Bench (Vals AI)81.3%48.7%Claude Sonnet 5
Code migration (Vals AI)44.4%26.8%Claude Sonnet 5
ProgramBench (Vals AI)0.0%0.0%Tie
IOI (Vals AI)45.0%Not measuredOnly Claude Sonnet 5 measured
Terminal-Bench 2.1 (Vals AI)74.5%74.2%Claude Sonnet 5
Vibe Code Bench 1-100 (Vals AI)13.8%Not measuredOnly Claude Sonnet 5 measured
SkillsBench (Vals AI)46.5%52.7%Gemini 3.5 Flash
CyberBench (Vals AI)70.3%Not measuredOnly Claude Sonnet 5 measured
SciCode54.3%53.9%Claude Sonnet 5
Terminal-Bench Hard (Artificial Analysis run)Not measured46.2%Only Gemini 3.5 Flash measured
FrontierCode42.7%Not measuredOnly Claude Sonnet 5 measured
GSO-Bench37.3%Not measuredOnly Claude Sonnet 5 measured
WeirdML68.8%62.6%Claude Sonnet 5
ALE-Bench1463.1911.0Claude Sonnet 5
LMArena Text: coding14831493Gemini 3.5 Flash
LMArena Text: software and IT14741494Gemini 3.5 Flash
LMArena WebDev: React15411495Claude Sonnet 5
LMArena WebDev: HTML15271522Claude Sonnet 5
LMArena WebDev: from an image15401504Claude Sonnet 5
SciCode10.7%12.3%Gemini 3.5 Flash
Neither model has a result on the other 13 boards here
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index20
Intelligence benchmarks for Claude Sonnet 5 and Gemini 3.5 Flash
BenchmarkClaude Sonnet 5Gemini 3.5 FlashLeader
AA Intelligence Index38.233.6Claude Sonnet 5
Epoch Capabilities Index156.9154.9Claude Sonnet 5
Agentic workLike-for-likePublic boards, shown as published, kept out of the index131
Agentic work benchmarks for Claude Sonnet 5 and Gemini 3.5 Flash
BenchmarkClaude Sonnet 5Gemini 3.5 FlashLeader
AA Agentic Index43.6Not measuredOnly Claude Sonnet 5 measured
Design Arena: agents building web apps12451202Claude Sonnet 5
Design Arena: agents building full-stack apps12491197Claude Sonnet 5
Design Arena: agents building mobile apps12151174Claude Sonnet 5
Design Arena: agents building Android apps12251184Claude Sonnet 5
Design Arena: agents building Godot games12251098Claude Sonnet 5
Design Arena: agents building games12271180Claude Sonnet 5
Design Arena: HTML slides12181142Claude Sonnet 5
Design Arena: PowerPoint slides12161179Claude Sonnet 5
Design Arena: spreadsheets1021Not measuredOnly Claude Sonnet 5 measured
LiveBench research82.8%Not measuredOnly Claude Sonnet 5 measured
LiveBench browser72.0%Not measuredOnly Claude Sonnet 5 measured
LiveBench long agentic39.0%Not measuredOnly Claude Sonnet 5 measured
SREBench (Vals AI)0.4%Not measuredOnly Claude Sonnet 5 measured
Finance Agent (Vals AI)53.9%57.9%Gemini 3.5 Flash
Tax Agent Bench (Vals AI)29.4%21.6%Claude Sonnet 5
Legal Research Bench (Vals AI)41.8%30.8%Claude Sonnet 5
Excel Modeling Benchmark (Vals AI)66.3%63.5%Claude Sonnet 5
Terminal-Bench-Science (Vals AI)5.7%5.7%Tie
τ²-Bench TelecomNot measured95.6%Only Gemini 3.5 Flash measured
APEX-Agents54.5%27.5%Claude Sonnet 5
Vending-Bench 2$6,378$5,396Claude Sonnet 5
Neither model has a result on the other 19 boards here
ReasoningLike-for-likePublic boards, shown as published, kept out of the index111
Reasoning benchmarks for Claude Sonnet 5 and Gemini 3.5 Flash
BenchmarkClaude Sonnet 5Gemini 3.5 FlashLeader
GPQA Diamond88.9%92.7%Gemini 3.5 Flash
LiveBench reasoning88.7%Not measuredOnly Claude Sonnet 5 measured
MMMU Pro (Vals AI)83.0%88.3%Gemini 3.5 Flash
GPQA Diamond (Artificial Analysis run)91.1%92.2%Gemini 3.5 Flash
Humanity's Last Exam (Artificial Analysis run)41.3%42.7%Gemini 3.5 Flash
GPQA Diamond (Epoch AI run)90.5%92.8%Gemini 3.5 Flash
ARC-AGINot measured92.5%Only Gemini 3.5 Flash measured
ARC-AGI-2Not measured72.1%Only Gemini 3.5 Flash measured
SimpleBench60.6%76.7%Gemini 3.5 Flash
Chess puzzles45.0%45.0%Tie
Mystery game puzzles35.0%32.0%Claude Sonnet 5
EBR-benchNot measured4.8%Only Gemini 3.5 Flash measured
LMArena Text: hard prompts14611488Gemini 3.5 Flash
LMArena Text: expert14891495Gemini 3.5 Flash
LMArena Text: hard prompts in English14641483Gemini 3.5 Flash
LMArena Vision: diagrams12931323Gemini 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 index33
Math benchmarks for Claude Sonnet 5 and Gemini 3.5 Flash
BenchmarkClaude Sonnet 5Gemini 3.5 FlashLeader
OTIS Mock AIME94.7%95.6%Gemini 3.5 Flash
FrontierMath, tiers 1 to 365.6%62.8%Claude Sonnet 5
FrontierMath, tier 429.3%26.8%Claude Sonnet 5
ProofBench77.0%31.0%Claude Sonnet 5
LMArena Text: math14671504Gemini 3.5 Flash
LMArena Text: mathematical work14811495Gemini 3.5 Flash
Neither model has a result on the other 7 boards here
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index47
Knowledge benchmarks for Claude Sonnet 5 and Gemini 3.5 Flash
BenchmarkClaude Sonnet 5Gemini 3.5 FlashLeader
MMLU Pro87.5%89.5%Gemini 3.5 Flash
LegalBench (Vals AI)83.9%83.6%Claude Sonnet 5
CorpFin (Vals AI)67.0%64.7%Claude Sonnet 5
TaxEval (Vals AI)75.6%74.4%Claude Sonnet 5
MortgageTax (Vals AI)70.0%68.1%Claude Sonnet 5
MedCode (Vals AI)47.5%55.8%Gemini 3.5 Flash
SimpleQA Verified33.7%66.2%Gemini 3.5 Flash
LMArena Text: science14601495Gemini 3.5 Flash
LMArena Text: medicine and healthcare14421483Gemini 3.5 Flash
LMArena Text: legal and government14541488Gemini 3.5 Flash
LMArena Text: business and finance14361467Gemini 3.5 Flash
FACTS Benchmark SuiteNot measured63.1%Only Gemini 3.5 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 index62
Web design benchmarks for Claude Sonnet 5 and Gemini 3.5 Flash
BenchmarkClaude Sonnet 5Gemini 3.5 FlashLeader
Design Arena: websites12741268Claude Sonnet 5
Design Arena: UI components12801273Claude Sonnet 5
Design Arena: game dev12781263Claude Sonnet 5
Design Arena: data viz12511236Claude Sonnet 5
Design Arena: 3D12611244Claude Sonnet 5
Design Arena: all code categories12761266Claude Sonnet 5
Design Arena: SVG11931254Gemini 3.5 Flash
Design Arena: ASCII art12071254Gemini 3.5 Flash
LiveBench design82.0%Not measuredOnly Claude Sonnet 5 measured
GeneralLike-for-likePublic boards, shown as published, kept out of the index626
General benchmarks for Claude Sonnet 5 and Gemini 3.5 Flash
BenchmarkClaude Sonnet 5Gemini 3.5 FlashLeader
LiveBench data analysis71.7%Not measuredOnly Claude Sonnet 5 measured
Public Benefits Bench (Vals AI)66.0%59.5%Claude Sonnet 5
SAGE (Vals AI)48.9%49.9%Gemini 3.5 Flash
MedScribe (Vals AI)76.0%76.6%Gemini 3.5 Flash
Vals Multimodal Index68.8%62.9%Claude Sonnet 5
IFBenchNot measured76.3%Only Gemini 3.5 Flash measured
Long context reasoning (AA-LCR)82.0%74.3%Claude Sonnet 5
DTBench92.5%94.7%Gemini 3.5 Flash
LMCA50.0%47.1%Claude Sonnet 5
Surface Evolver Bench60.0%58.1%Claude Sonnet 5
LMArena Text14421482Gemini 3.5 Flash
LMArena Text: instruction following14521467Gemini 3.5 Flash
LMArena Text: creative writing14161470Gemini 3.5 Flash
LMArena Vision12731308Gemini 3.5 Flash
LMArena Text: English14501481Gemini 3.5 Flash
LMArena Text: non-English14311475Gemini 3.5 Flash
LMArena Text: Chinese14781527Gemini 3.5 Flash
LMArena Text: German14421494Gemini 3.5 Flash
LMArena Text: Japanese14221486Gemini 3.5 Flash
LMArena Text: Korean14121448Gemini 3.5 Flash
LMArena Text: French14631490Gemini 3.5 Flash
LMArena Text: Spanish14381480Gemini 3.5 Flash
LMArena Text: Russian14501493Gemini 3.5 Flash
LMArena Text: Polish14251516Gemini 3.5 Flash
LMArena Text: multi-turn14531481Gemini 3.5 Flash
LMArena Text: longer queries14621483Gemini 3.5 Flash
LMArena Text: writing and language14361478Gemini 3.5 Flash
LMArena Text: entertainment and media14111459Gemini 3.5 Flash
LMArena Vision: English12751305Gemini 3.5 Flash
LMArena Vision: Chinese13311377Gemini 3.5 Flash
LMArena Vision: reading text12881317Gemini 3.5 Flash
LMArena Vision: humor12611321Gemini 3.5 Flash
LMArena Vision: creative writing12461301Gemini 3.5 Flash
LMArena Document14661463Claude Sonnet 5
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 Claude Sonnet 5 and Gemini 3.5 Flash
BenchmarkClaude Sonnet 5Gemini 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 5$0.0070Fits 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 5$0.130Fits 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 5$0.500Fits 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 5 and Gemini 3.5 Flash
SpecificationAnthropic Claude Sonnet 5Google Gemini 3.5 Flash
MakerAnthropicGoogle
WeightsNo public weights listedNo public weights listed
ReleasedJune 30, 2026May 19, 2026
Context window1M1.05M
Input $/Mtok$2.00$1.50
Output $/Mtok$10.00$9.00
Coding index57.739.8
Independent measurements behind it64
Cost per solved task$1.87$1.21
SourceOpenRouter listingOpenRouter listing

Questions

Is Claude Sonnet 5 better than Gemini 3.5 Flash for coding?

Pick Claude Sonnet 5 for coding: it scores 57.7 on the Vibe Coding Index against 39.8 for Gemini 3.5 Flash. Pick Gemini 3.5 Flash for output tokens 1.1x cheaper ($9.00 vs $10.00 per million) and a lower cost per solved task ($1.21 against $1.87).

Which is cheaper, Claude Sonnet 5 or Gemini 3.5 Flash?

Claude Sonnet 5 costs $2.00 per million input tokens and $10.00 per million output tokens; Gemini 3.5 Flash costs $1.50 and $9.00. Per solved SWE-bench Verified task, Claude Sonnet 5 costs $1.87 and Gemini 3.5 Flash $1.21.

Which has the bigger context window, Claude Sonnet 5 or Gemini 3.5 Flash?

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

How many benchmarks is the Claude Sonnet 5 vs Gemini 3.5 Flash comparison based on?

105 benchmarks have a result for both models as of October 21, 2026. Claude Sonnet 5's coding index rests on 6 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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