Claude Opus 4.1 vs Gemini 3.5 Flash

Gemini 3.5 Flash leads Claude Opus 4.1 on the Artificial Analysis Intelligence Index, 33.6 to 22.8, and Gemini 3.5 Flash costs 8.3x less per output token ($9.00 vs $75.00 per million). Updated October 21, 2026; 62 benchmarks have a result for both.

Replace Claude Opus 4.1 Replace Gemini 3.5 Flash

Claude Opus 4.1Anthropic

Coding: No data
Overall: 50.2
Output $/M: $75.00

Gemini 3.5 FlashGoogle

Coding: 39.8
Overall: 63.8
Output $/M: $9.00

vs boards won of 62 shared

Claude Opus 4.1 or Gemini 3.5 Flash: which to pick

Only Gemini 3.5 Flash has a coding score, 39.8 on the Vibe Coding Index; Claude Opus 4.1 has none, so the two cannot be ranked on coding.

Pick Claude Opus 4.1 for work measured by EBR-bench, where it leads.

Model AClaude Opus 4.1AnthropicNot benchmarked1 independent benchmarkNo cost per solved task Model BGemini 3.5 FlashGoogle39.8/1004 independent benchmarks$1.21 per solved task

621150

Shared results: 62
Claude Opus 4.1 only: 11
Gemini 3.5 Flash only: 50
Like-for-like categories: 7 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.

Coding
Vibe Coding Index, six public coding benchmarks
No call
Only Gemini 3.5 Flash has a coding score, so no call is made.
One side not measured
Intelligence
AA Intelligence Index
Gemini 3.5 Flash
Gemini 3.5 Flash leads, 33.6 against 22.8.
Same board, both measured
Reasoning
GPQA Diamond
Gemini 3.5 Flash
Gemini 3.5 Flash leads, 92.7% against 76.3%.
Same board, both measured
Math
AIME
No call
Only Claude Opus 4.1 has a AIME result, 78.2%.
Directional only
Knowledge
MMLU Pro
Gemini 3.5 Flash
Gemini 3.5 Flash leads, 89.5% against 87.9%.
Same board, both measured
Web design
Design Arena: websites
Gemini 3.5 Flash
Gemini 3.5 Flash leads, 1268 against 1177.
Same board, both measured
Long documents
Listed context window
Gemini 3.5 Flash
Gemini 3.5 Flash takes 1.05M tokens against 200K.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
Gemini 3.5 Flash
Claude Opus 4.1 $0.052, Gemini 3.5 Flash $0.0060 per turn.
List prices
Cost per solved task
One SWE-bench Verified task, solved
No call
Only Gemini 3.5 Flash has the number, $1.21.
Directional only

At a glance

Coding index: Claude Opus 4.1 not benchmarked, Gemini 3.5 Flash 39.8 from 4 benchmarks.
Widest category: Math, 24.7 points apart on average over 5 shared benchmarks.
Widest single gap: FrontierMath, tiers 1 to 3: Claude Opus 4.1 12.6% against Gemini 3.5 Flash 62.8%, 50.2 points apart on a 0 to 100 scale.
Output price: Claude Opus 4.1 $75.00 against Gemini 3.5 Flash $9.00 per million output tokens, 8.3x apart.
Context window: Claude Opus 4.1 takes 200K 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
Category	Claude Opus 4.1	Gemini 3.5 Flash
Coding	0	7
Intelligence	0	2
Reasoning	1	8
Math	0	5
Knowledge	0	10
Web design	0	8
General	0	21
All shared boards	1	61

CodingLike-for-likeSix of these boards feed the Vibe Coding Index07

Coding benchmarks for Claude Opus 4.1 and Gemini 3.5 Flash
Benchmark	Claude Opus 4.1	Gemini 3.5 Flash	Leader
LMArena WebDev	1390	1499	Gemini 3.5 Flash
LiveCodeBench (Vals AI)	66.5%	87.6%	Gemini 3.5 Flash
SWE-bench Verified (Vals AI)	Not measured	78.8%	Only Gemini 3.5 Flash measured
Terminal-Bench 4 (Vals AI)	Not measured	6.1%	Only Gemini 3.5 Flash measured
Vibe Code Bench (Vals AI)	Not measured	48.7%	Only Gemini 3.5 Flash measured
Code migration (Vals AI)	Not measured	26.8%	Only Gemini 3.5 Flash measured
ProgramBench (Vals AI)	Not measured	0.0%	Only Gemini 3.5 Flash measured
Terminal-Bench 2.1 (Vals AI)	Not measured	74.2%	Only Gemini 3.5 Flash measured
SkillsBench (Vals AI)	Not measured	52.7%	Only Gemini 3.5 Flash measured
SciCode	Not measured	53.9%	Only Gemini 3.5 Flash measured
Terminal-Bench Hard (Artificial Analysis run)	Not measured	46.2%	Only Gemini 3.5 Flash measured
Terminal-Bench	38.0%	Not measured	Only Claude Opus 4.1 measured
WeirdML	45.9%	62.6%	Gemini 3.5 Flash
Cybench	42.0%	Not measured	Only Claude Opus 4.1 measured
ALE-Bench	Not measured	911.0	Only Gemini 3.5 Flash measured
LMArena Text: coding	1479	1493	Gemini 3.5 Flash
LMArena Text: software and IT	1456	1494	Gemini 3.5 Flash
LMArena WebDev: React	Not measured	1495	Only Gemini 3.5 Flash measured
LMArena WebDev: HTML	1399	1522	Gemini 3.5 Flash
LMArena WebDev: from an image	Not measured	1504	Only Gemini 3.5 Flash measured
SciCode	4.6%	12.3%	Gemini 3.5 Flash
Neither model has a result on the other 18 boards here

IntelligenceLike-for-likePublic boards, shown as published, kept out of the index02

Intelligence benchmarks for Claude Opus 4.1 and Gemini 3.5 Flash
Benchmark	Claude Opus 4.1	Gemini 3.5 Flash	Leader
AA Intelligence Index	22.8	33.6	Gemini 3.5 Flash
Epoch Capabilities Index	144.1	154.9	Gemini 3.5 Flash

Agentic workDirectional onlyPublic boards, shown as published, kept out of the index19 boards, none shared

Agentic work benchmarks for Claude Opus 4.1 and Gemini 3.5 Flash
Benchmark	Claude Opus 4.1	Gemini 3.5 Flash	Leader
Design Arena: agents building web apps	Not measured	1202	Only Gemini 3.5 Flash measured
Design Arena: agents building full-stack apps	Not measured	1197	Only Gemini 3.5 Flash measured
Design Arena: agents building mobile apps	Not measured	1174	Only Gemini 3.5 Flash measured
Design Arena: agents building Android apps	Not measured	1184	Only Gemini 3.5 Flash measured
Design Arena: agents building Godot games	Not measured	1098	Only Gemini 3.5 Flash measured
Design Arena: agents building games	Not measured	1180	Only Gemini 3.5 Flash measured
Design Arena: HTML slides	Not measured	1142	Only Gemini 3.5 Flash measured
Design Arena: PowerPoint slides	Not measured	1179	Only Gemini 3.5 Flash measured
Finance Agent (Vals AI)	Not measured	57.9%	Only Gemini 3.5 Flash measured
Tax Agent Bench (Vals AI)	Not measured	21.6%	Only Gemini 3.5 Flash measured
Legal Research Bench (Vals AI)	Not measured	30.8%	Only Gemini 3.5 Flash measured
Excel Modeling Benchmark (Vals AI)	Not measured	63.5%	Only Gemini 3.5 Flash measured
Terminal-Bench-Science (Vals AI)	Not measured	5.7%	Only Gemini 3.5 Flash measured
τ²-Bench Telecom	Not measured	95.6%	Only Gemini 3.5 Flash measured
APEX-Agents	Not measured	27.5%	Only Gemini 3.5 Flash measured
METR time horizons	66.8%	Not measured	Only Claude Opus 4.1 measured
GDPval	43.6%	Not measured	Only Claude Opus 4.1 measured
DeepResearch Bench	48.3%	Not measured	Only Claude Opus 4.1 measured
Vending-Bench 2	Not measured	$5,396	Only Gemini 3.5 Flash measured
Neither model has a result on the other 22 boards here

ReasoningLike-for-likePublic boards, shown as published, kept out of the index18

Reasoning benchmarks for Claude Opus 4.1 and Gemini 3.5 Flash
Benchmark	Claude Opus 4.1	Gemini 3.5 Flash	Leader
GPQA Diamond	76.3%	92.7%	Gemini 3.5 Flash
MMMU Pro (Vals AI)	77.5%	88.3%	Gemini 3.5 Flash
GPQA Diamond (Artificial Analysis run)	Not measured	92.2%	Only Gemini 3.5 Flash measured
Humanity's Last Exam (Artificial Analysis run)	Not measured	42.7%	Only Gemini 3.5 Flash measured
GPQA Diamond (Epoch AI run)	77.3%	92.8%	Gemini 3.5 Flash
ARC-AGI	Not measured	92.5%	Only Gemini 3.5 Flash measured
ARC-AGI-2	Not measured	72.1%	Only Gemini 3.5 Flash measured
SimpleBench	60.0%	76.7%	Gemini 3.5 Flash
Chess puzzles	Not measured	45.0%	Only Gemini 3.5 Flash measured
Mystery game puzzles	21.0%	32.0%	Gemini 3.5 Flash
EBR-bench	7.9%	4.8%	Claude Opus 4.1
VPCT	35.0%	Not measured	Only Claude Opus 4.1 measured
LMArena Text: hard prompts	1442	1488	Gemini 3.5 Flash
LMArena Text: expert	1438	1495	Gemini 3.5 Flash
LMArena Text: hard prompts in English	1451	1483	Gemini 3.5 Flash
LMArena Vision: diagrams	Not measured	1323	Only Gemini 3.5 Flash measured
LMArena Vision: homework	Not measured	1330	Only Gemini 3.5 Flash measured
Neither model has a result on the other 5 boards here

MathLike-for-likePublic boards, shown as published, kept out of the index05

Math benchmarks for Claude Opus 4.1 and Gemini 3.5 Flash
Benchmark	Claude Opus 4.1	Gemini 3.5 Flash	Leader
AIME	78.2%	Not measured	Only Claude Opus 4.1 measured
MATH 500 (Vals AI)	95.4%	Not measured	Only Claude Opus 4.1 measured
MGSM (Vals AI)	94.4%	Not measured	Only Claude Opus 4.1 measured
OTIS Mock AIME	68.9%	95.6%	Gemini 3.5 Flash
FrontierMath, tiers 1 to 3	12.6%	62.8%	Gemini 3.5 Flash
FrontierMath, tier 4	2.4%	26.8%	Gemini 3.5 Flash
ProofBench	Not measured	31.0%	Only Gemini 3.5 Flash measured
LMArena Text: math	1431	1504	Gemini 3.5 Flash
LMArena Text: mathematical work	1434	1495	Gemini 3.5 Flash
Neither model has a result on the other 4 boards here

KnowledgeLike-for-likePublic boards, shown as published, kept out of the index010

Knowledge benchmarks for Claude Opus 4.1 and Gemini 3.5 Flash
Benchmark	Claude Opus 4.1	Gemini 3.5 Flash	Leader
MMLU Pro	87.9%	89.5%	Gemini 3.5 Flash
LegalBench (Vals AI)	83.5%	83.6%	Gemini 3.5 Flash
CorpFin (Vals AI)	Not measured	64.7%	Only Gemini 3.5 Flash measured
TaxEval (Vals AI)	73.7%	74.4%	Gemini 3.5 Flash
MortgageTax (Vals AI)	61.1%	68.1%	Gemini 3.5 Flash
MedQA (Vals AI)	93.6%	Not measured	Only Claude Opus 4.1 measured
MedCode (Vals AI)	47.2%	55.8%	Gemini 3.5 Flash
SimpleQA Verified	Not measured	66.2%	Only Gemini 3.5 Flash measured
LMArena Text: science	1422	1495	Gemini 3.5 Flash
LMArena Text: medicine and healthcare	1416	1483	Gemini 3.5 Flash
LMArena Text: legal and government	1421	1488	Gemini 3.5 Flash
LMArena Text: business and finance	1406	1467	Gemini 3.5 Flash
FACTS Benchmark Suite	40.4%	63.1%	Gemini 3.5 Flash
Neither model has a result on the other 5 boards here

Web designLike-for-likePublic boards, shown as published, kept out of the index08

Web design benchmarks for Claude Opus 4.1 and Gemini 3.5 Flash
Benchmark	Claude Opus 4.1	Gemini 3.5 Flash	Leader
Design Arena: websites	1177	1268	Gemini 3.5 Flash
Design Arena: UI components	1165	1273	Gemini 3.5 Flash
Design Arena: game dev	1171	1263	Gemini 3.5 Flash
Design Arena: data viz	1166	1236	Gemini 3.5 Flash
Design Arena: 3D	1153	1244	Gemini 3.5 Flash
Design Arena: all code categories	1171	1266	Gemini 3.5 Flash
Design Arena: SVG	1152	1254	Gemini 3.5 Flash
Design Arena: ASCII art	1167	1254	Gemini 3.5 Flash
Neither model has a result on the other 1 board here

GeneralLike-for-likePublic boards, shown as published, kept out of the index021

General benchmarks for Claude Opus 4.1 and Gemini 3.5 Flash
Benchmark	Claude Opus 4.1	Gemini 3.5 Flash	Leader
Public Benefits Bench (Vals AI)	Not measured	59.5%	Only Gemini 3.5 Flash measured
SAGE (Vals AI)	31.4%	49.9%	Gemini 3.5 Flash
MedScribe (Vals AI)	73.9%	76.6%	Gemini 3.5 Flash
Vals Multimodal Index	Not measured	62.9%	Only Gemini 3.5 Flash measured
IFBench	Not measured	76.3%	Only Gemini 3.5 Flash measured
Long context reasoning (AA-LCR)	Not measured	74.3%	Only Gemini 3.5 Flash measured
DTBench	80.0%	94.7%	Gemini 3.5 Flash
LMCA	37.1%	47.1%	Gemini 3.5 Flash
Creative writing (Lech Mazur)	84.7%	Not measured	Only Claude Opus 4.1 measured
Surface Evolver Bench	Not measured	58.1%	Only Gemini 3.5 Flash measured
LMArena Text	1419	1482	Gemini 3.5 Flash
LMArena Text: instruction following	1435	1467	Gemini 3.5 Flash
LMArena Text: creative writing	1412	1470	Gemini 3.5 Flash
LMArena Vision	Not measured	1308	Only Gemini 3.5 Flash measured
LMArena Text: English	1433	1481	Gemini 3.5 Flash
LMArena Text: non-English	1405	1475	Gemini 3.5 Flash
LMArena Text: Chinese	1427	1527	Gemini 3.5 Flash
LMArena Text: German	1413	1494	Gemini 3.5 Flash
LMArena Text: Japanese	1377	1486	Gemini 3.5 Flash
LMArena Text: Korean	1381	1448	Gemini 3.5 Flash
LMArena Text: French	1433	1490	Gemini 3.5 Flash
LMArena Text: Spanish	1448	1480	Gemini 3.5 Flash
LMArena Text: Russian	1422	1493	Gemini 3.5 Flash
LMArena Text: Polish	1413	1516	Gemini 3.5 Flash
LMArena Text: multi-turn	1444	1481	Gemini 3.5 Flash
LMArena Text: longer queries	1455	1483	Gemini 3.5 Flash
LMArena Text: writing and language	1418	1478	Gemini 3.5 Flash
LMArena Text: entertainment and media	1398	1459	Gemini 3.5 Flash
LMArena Vision: English	Not measured	1305	Only Gemini 3.5 Flash measured
LMArena Vision: Chinese	Not measured	1377	Only Gemini 3.5 Flash measured
LMArena Vision: reading text	Not measured	1317	Only Gemini 3.5 Flash measured
LMArena Vision: humor	Not measured	1321	Only Gemini 3.5 Flash measured
LMArena Vision: creative writing	Not measured	1301	Only Gemini 3.5 Flash measured
LMArena Document	Not measured	1463	Only Gemini 3.5 Flash 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 Claude Opus 4.1 and Gemini 3.5 Flash
Benchmark	Claude Opus 4.1	Gemini 3.5 Flash	Leader
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 Opus 4.1$0.052Fits 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 Opus 4.1$0.975Fits 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 Opus 4.1$3.75Exceeds the context window

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 Opus 4.1 and Gemini 3.5 Flash
Specification	Anthropic Claude Opus 4.1	Google Gemini 3.5 Flash
Maker	Anthropic	Google
Weights	No public weights listed	No public weights listed
Released	August 5, 2025	May 19, 2026
Context window	200K	1.05M
Input $/Mtok	$15.00	$1.50
Output $/Mtok	$75.00	$9.00
Coding index	Not benchmarked	39.8
Independent measurements behind it	1	4
Cost per solved task	Not computable	$1.21
Source	OpenRouter listing	OpenRouter listing

Questions

Is Claude Opus 4.1 better than Gemini 3.5 Flash for coding?

Only Gemini 3.5 Flash has a coding score, 39.8 on the Vibe Coding Index; Claude Opus 4.1 has none, so the two cannot be ranked on coding. Pick Claude Opus 4.1 for work measured by EBR-bench, where it leads.

Which is cheaper, Claude Opus 4.1 or Gemini 3.5 Flash?

Claude Opus 4.1 costs $15.00 per million input tokens and $75.00 per million output tokens; Gemini 3.5 Flash costs $1.50 and $9.00. Cost per solved task is known for Gemini 3.5 Flash only.

Which has the bigger context window, Claude Opus 4.1 or Gemini 3.5 Flash?

Gemini 3.5 Flash, with 1.05M tokens against 200K.

How many benchmarks is the Claude Opus 4.1 vs Gemini 3.5 Flash comparison based on?

62 benchmarks have a result for both models as of October 21, 2026. Claude Opus 4.1's coding index rests on 1 independent benchmark and Gemini 3.5 Flash's on 4. Where only one model has a result, the page says so instead of naming a winner.

Claude Opus 4.1 or Gemini 3.5 Flash: which to pick

Which one for your work

Coding

Intelligence

Reasoning

Math

Knowledge

Web design

Long documents

Everyday cost

Cost per solved task

At a glance

Benchmark by benchmark

What each workload costs

Chat turn

Repository review

Agent loop

Specification differences

Questions

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