Why is this comparison indexable?

It has 4 verifiable comparison points, and both models have pricing or benchmark data.

Are missing metrics invented?

No. Metrics without LMSpeed data are omitted from this report.

Back to models

Data points: 143

Model compare

Claude Sonnet 4.6 vs Gemini 3.5 Flash

The readout for Claude Sonnet 4.6 and Gemini 3.5 Flash, before the detailed comparison sheet.

Model A

Claude Sonnet 4.6

Anthropic

Contender

vs

Model B

Gemini 3.5 Flash

Google

Leading

Key Takeaways

Weighted outcome: Gemini 3.5 Flash. Benchmark capability categories carry 80%, while price, API performance, and availability carry 20%.

Decision read

Gemini 3.5 Flash

Gemini 3.5 Flash has the higher weighted result; Model A / B score 42.9 to 57.1.

Evidence depth

143 data points

Includes 35 benchmark rows, 2 audit samples, and 8 provider examples.

Selection signal

Start with Gemini 3.5 Flash

The charts below split 45 high-signal samples across speed, scores, and audit health.

Change comparison

Switch either side of this report to compare another model with the same LMSpeed data pipeline.

Model AModel B

Comparison sheet

This report only uses LMSpeed data for Claude Sonnet 4.6 and Gemini 3.5 Flash: pricing, speed aggregates, third-party benchmark scores, and shared provider samples.

Model compare	Claude Sonnet 4.6	Gemini 3.5 Flash
Overall leader	Contender	Leading
Weighted overall score	42.9 pts	57.1 pts
Benchmark category leads	2 categories	5 categories
Operational advantages	Cheapest input price, Free providers, Provider coverage	No data
Context window	1M tokens	1.0M tokens
Max output	128K tokens	65.5K tokens
Modalities	Input TextImageFile Output Text

The overall result weights benchmark capability categories at 80% and price, API speed/latency, and availability at 20%. Recent test volume does not affect the winner, and missing benchmark categories are excluded.

Model metadata

Model compare	Claude Sonnet 4.6	Gemini 3.5 Flash
Developer	Anthropic	Google
Released	Feb 2026	May 2026
Parameters	No data	No data
Tokenizer	Claude	Gemini
Knowledge cutoff	No data	2025-01-01
OpenRouter ID	anthropic/claude-sonnet-4.6	google/gemini-3.5-flash
References	No data	No data

When to choose each model

This report only uses LMSpeed data for Claude Sonnet 4.6 and Gemini 3.5 Flash: pricing, speed aggregates, third-party benchmark scores, and shared provider samples.

Claude Sonnet 4.6

Claude Sonnet 4.6 is stronger in benchmark categories (Coding, Knowledge) and operational dimensions (Cheapest input price, Free providers, Provider coverage).

Gemini 3.5 Flash

Gemini 3.5 Flash leads these benchmark categories: Agents, Reasoning, Math, Multimodal, Instruction following.

Benchmark score comparison

Third-party benchmark profile synced into LMSpeed; only metrics available for both models are shown.

Category performance

Compare benchmark category scores on a 0-100 scale. Select a category to inspect the gap.

Model A coverage: 7 / 8
Model B coverage: 7 / 8
Shared: 7 shared categories

Avg. score

Claude Sonnet 4.6

53.2

Avg. score

Gemini 3.5 Flash

56.3

Agents

Gemini 3.5 Flash leads by 5.9

Claude Sonnet 4.653.6

Gemini 3.5 Flash59.5

Coding

Claude Sonnet 4.6 leads by 1.8

Claude Sonnet 4.656.5

Gemini 3.5 Flash54.7

Reasoning

Gemini 3.5 Flash leads by 4.3

Claude Sonnet 4.6

Professional benchmark details

Metric-level scores with benchmark source, rank depth, confidence, error, and evaluation date where available.

Group

Aggregatereported

BenchLM overall score

SourceClaude Sonnet 4.6

Claude Sonnet 4.6

64.0

Rank #24/83 · confidence 3 · eval date 2026-02-01

+7.0

Gemini 3.5 Flash

winner

71.0

Rank #16/83 · confidence 4 · eval date 2026-05-19

Performanceverified

Output speed

SourceClaude Sonnet 4.6 (Adaptive Reasoning, Max Effort)

Claude Sonnet 4.6

74.6 tok/s

Rank #83/139 · confidence 4

+165.5 tok/s

Gemini 3.5 Flash

winner

240.1 tok/s

Rank #9/139 · confidence 4

Performanceverified

Time to first answer token

SourceClaude Sonnet 4.6 (Adaptive Reasoning, Max Effort)

Claude Sonnet 4.6

73.67 s

Rank #129/139 · confidence 4

+63.20 s

Gemini 3.5 Flash

winner

10.48 s

Rank #75/139 · confidence 4

Performanceverified

Time to first token

SourceClaude Sonnet 4.6 (Adaptive Reasoning, Max Effort)

Claude Sonnet 4.6

73.67 s

Rank #133/139 · confidence 4

+63.20 s

Gemini 3.5 Flash

winner

10.48 s

Rank #117/139 · confidence 4

Pricingverified

Blended price

SourceClaude Sonnet 4.6 (Adaptive Reasoning, Max Effort)

Claude Sonnet 4.6

$6.00/M

Rank #139/163 · confidence 4

+$2.63/M

Gemini 3.5 Flash

winner

$3.38/M

Rank #118/163 · confidence 4

Pricingverified

Input price

SourceClaude Sonnet 4.6 (Adaptive Reasoning, Max Effort)

Claude Sonnet 4.6

$3.00/M

Rank #139/163 · confidence 4

+$1.50/M

Gemini 3.5 Flash

winner

$1.50/M

Rank #120/163 · confidence 4

Pricingverified

Output price

SourceClaude Sonnet 4.6 (Adaptive Reasoning, Max Effort)

Claude Sonnet 4.6

$15.00/M

Rank #138/163 · confidence 4

+$6.00/M

Gemini 3.5 Flash

winner

$9.00/M

Rank #121/163 · confidence 4

Reasoningverified

GPQA

SourceClaude Sonnet 4.6 (Adaptive Reasoning, Max Effort)

Claude Sonnet 4.6

87.5%

Rank #30/187 · confidence 4

+4.7%

Gemini 3.5 Flash

winner

92.2%

Rank #9/187 · confidence 4

Reasoningverified

HLE

SourceClaude Sonnet 4.6 (Adaptive Reasoning, Max Effort)

Claude Sonnet 4.6

30.0%

Rank #30/186 · confidence 4

+11.0%

Gemini 3.5 Flash

winner

41.0%

Rank #9/186 · confidence 4

Reasoningreported

CritPt

SourceClaude Sonnet 4.6

Claude Sonnet 4.6

0.9

Rank #60/73 · confidence 3 · eval date 2026-02-01

+12.2

Gemini 3.5 Flash

winner

13.1

Rank #16/73 · confidence 4 · eval date 2026-05-19

Reasoningreported

AA-LCR

SourceClaude Sonnet 4.6

Claude Sonnet 4.6

57.7

Rank #63/89 · confidence 3 · eval date 2026-02-01

+11.6

Gemini 3.5 Flash

winner

69.3

Rank #22/89 · confidence 4 · eval date 2026-05-19

Codingreported

CursorBench v3.1

SourceClaude Sonnet 4.6

Claude Sonnet 4.6

48.8

Rank #5/6 · confidence 3 · eval date 2026-02-01

+1.0

Gemini 3.5 Flash

winner

49.8

Rank #4/6 · confidence 4 · eval date 2026-05-19

Codingreported

Vibe Code Bench

SourceClaude Sonnet 4.6

Claude Sonnet 4.6

winner

51.5

Rank #7/33 · confidence 3 · eval date 2026-02-01

+2.8

Gemini 3.5 Flash

48.7

Rank #9/33 · confidence 4 · eval date 2026-05-19

Codingreported

BenchLM Coding score

SourceClaude Sonnet 4.6

Claude Sonnet 4.6

winner

67.4

Rank #8/64 · confidence 3 · eval date 2026-02-01

+8.9

Gemini 3.5 Flash

58.5

Rank #28/64 · confidence 4 · eval date 2026-05-19

Codingverified

SciCode

SourceClaude Sonnet 4.6 (Adaptive Reasoning, Max Effort)

Claude Sonnet 4.6

46.8%

Rank #28/184 · confidence 4

+6.3%

Gemini 3.5 Flash

winner

53.1%

Rank #11/184 · confidence 4

Codingreported

AA-SciCode

SourceClaude Sonnet 4.6

Claude Sonnet 4.6

46.9

Rank #33/96 · confidence 3 · eval date 2026-02-01

+6.2

Gemini 3.5 Flash

winner

53.1

Rank #15/96 · confidence 4 · eval date 2026-05-19

Mathreported

FrontierMath v2 (Tiers 1-3)

SourceClaude Sonnet 4.6

Claude Sonnet 4.6

32.4

Rank #18/47 · confidence 3 · eval date 2026-02-01

+6.6

Gemini 3.5 Flash

winner

39.0

Rank #12/47 · confidence 4 · eval date 2026-05-19

Mathreported

FrontierMath v2 (Tier 4)

SourceClaude Sonnet 4.6

Claude Sonnet 4.6

8.3

Rank #19/35 · confidence 3 · eval date 2026-02-01

+6.3

Gemini 3.5 Flash

winner

14.6

Rank #14/35 · confidence 4 · eval date 2026-05-19

Mathreported

BenchLM Math score

SourceClaude Sonnet 4.6

Claude Sonnet 4.6

49.5

Rank #31/56 · confidence 3 · eval date 2026-02-01

+6.5

Gemini 3.5 Flash

winner

56.0

Rank #27/56 · confidence 4 · eval date 2026-05-19

Knowledgereported

AA-Omniscience Accuracy

SourceClaude Sonnet 4.6

Claude Sonnet 4.6

38.0

Rank #29/90 · confidence 3 · eval date 2026-02-01

+13.9

Gemini 3.5 Flash

winner

51.9

Rank #7/90 · confidence 4 · eval date 2026-05-19

Knowledgereported

AA-HLE

SourceClaude Sonnet 4.6

Claude Sonnet 4.6

13.2

Rank #63/96 · confidence 3 · eval date 2026-02-01

+27.8

Gemini 3.5 Flash

winner

41.0

Rank #8/96 · confidence 4 · eval date 2026-05-19

Knowledgereported

AA-GPQA Diamond

SourceClaude Sonnet 4.6

Claude Sonnet 4.6

79.9

Rank #63/96 · confidence 3 · eval date 2026-02-01

+12.3

Gemini 3.5 Flash

winner

92.2

Rank #9/96 · confidence 4 · eval date 2026-05-19

Knowledgereported

Artificial Analysis Intelligence Index

SourceClaude Sonnet 4.6

Claude Sonnet 4.6

35.9

Rank #43/99 · confidence 3 · eval date 2026-02-01

+14.3

Gemini 3.5 Flash

winner

50.2

Rank #12/99 · confidence 4 · eval date 2026-05-19

Knowledgereported

BenchLM Knowledge score

SourceClaude Sonnet 4.6

Claude Sonnet 4.6

winner

79.7

Rank #16/54 · confidence 3 · eval date 2026-02-01

+13.5

Gemini 3.5 Flash

66.2

Rank #32/54 · confidence 4 · eval date 2026-05-19

Knowledgereported

AA-Omniscience Hallucination Rate

SourceClaude Sonnet 4.6

Claude Sonnet 4.6

winner

65.9

Rank #58/90 · confidence 3 · eval date 2026-02-01

+5.2

Gemini 3.5 Flash

60.7

Rank #62/90 · confidence 4 · eval date 2026-05-19

Multimodalreported

AA-MMMU-Pro

SourceClaude Sonnet 4.6

Claude Sonnet 4.6

70.6

Rank #40/57 · confidence 3 · eval date 2026-02-01

+13.7

Gemini 3.5 Flash

winner

84.3

Rank #1/57 · confidence 4 · eval date 2026-05-19

Multimodalreported

BenchLM Multimodal Grounded score

SourceClaude Sonnet 4.6

Claude Sonnet 4.6

56.5

Rank #24/34 · confidence 3 · eval date 2026-02-01

+27.5

Gemini 3.5 Flash

winner

84.0

Rank #4/34 · confidence 4 · eval date 2026-05-19

Multimodalreported

CharXiv

SourceClaude Sonnet 4.6

Claude Sonnet 4.6

77.4

Rank #16/21 · confidence 3 · eval date 2026-02-01

+6.8

Gemini 3.5 Flash

winner

84.2

Rank #5/21 · confidence 4 · eval date 2026-05-19

Multimodalreported

Design Arena Website

SourceClaude Sonnet 4.6

Claude Sonnet 4.6

winner

1317.0

Rank #7/65 · confidence 3 · eval date 2026-02-01

+30.0

Gemini 3.5 Flash

1287.0

Rank #18/65 · confidence 4 · eval date 2026-05-19

Instruction followingreported

AA-IFBench

SourceClaude Sonnet 4.6

Claude Sonnet 4.6

41.2

Rank #69/86 · confidence 3 · eval date 2026-02-01

+35.1

Gemini 3.5 Flash

winner

76.3

Rank #13/86 · confidence 4 · eval date 2026-05-19

Agentsreported

OSWorld-Verified

SourceClaude Sonnet 4.6

Claude Sonnet 4.6

72.1

Rank #11/21 · confidence 3 · eval date 2026-02-01

+6.3

Gemini 3.5 Flash

winner

78.4

Rank #5/21 · confidence 4 · eval date 2026-05-19

Agentsreported

Gert Labs

SourceClaude Sonnet 4.6

Claude Sonnet 4.6

winner

62.9

Rank #8/50 · confidence 3 · eval date 2026-02-01

+1.1

Gemini 3.5 Flash

61.9

Rank #10/50 · confidence 4 · eval date 2026-05-19

Agentsreported

Terminal-Bench 2.0

SourceClaude Sonnet 4.6

Claude Sonnet 4.6

59.1

Rank #29/45 · confidence 3 · eval date 2026-02-01

+17.1

Gemini 3.5 Flash

winner

76.2

Rank #10/45 · confidence 4 · eval date 2026-05-19

Agentsreported

BenchLM Agentic score

SourceClaude Sonnet 4.6

Claude Sonnet 4.6

54.9

Rank #29/52 · confidence 3 · eval date 2026-02-01

+22.8

Gemini 3.5 Flash

winner

77.7

Rank #12/52 · confidence 4 · eval date 2026-05-19

Agentsreported

τ²-bench results

SourceClaude Sonnet 4.6

Claude Sonnet 4.6

79.5

Rank #55/84 · confidence 3 · eval date 2026-02-01

+15.8

Gemini 3.5 Flash

winner

95.3

Rank #17/84 · confidence 4 · eval date 2026-05-19

API audit comparison

Latest completed audits from shared providers, with four safety and integrity score groups plus report links.

Provider	Claude Sonnet 4.6	Gemini 3.5 Flash
Winner: Claude Sonnet 4.6	Claude Sonnet 4.6 claude-sonnet-4-6 Audit score 94 76100100100	Gemini 3.5 Flash gemini-3.5-flash No audit yet
Winner: Claude Sonnet 4.6	Claude Sonnet 4.6 claude-sonnet-4-6 Audit score 89 56100100100	Gemini 3.5 Flash gemini-3.5-flash No audit yet

Provider examples

Speed aggregates and input/output pricing share each provider row for real API selection and migration cost checks.

Provider	Claude Sonnet 4.6	Gemini 3.5 Flash
25 tests	Claude Sonnet 4.6 speed / latency 32 tok/s / 6074ms input / output No data	Gemini 3.5 Flash speed / latency N/A / N/A input / output No data
10 tests	Claude Sonnet 4.6 speed / latency 41 tok/s / 3714ms input / output No data	Gemini 3.5 Flash speed / latency N/A / N/A input / output No data
10 tests	Claude Sonnet 4.6 speed / latency 48 tok/s / 1587ms input / output No data	Gemini 3.5 Flash speed / latency N/A / N/A input / output No data
5 tests	Claude Sonnet 4.6 speed / latency 43 tok/s / 2401ms input / output No data	Gemini 3.5 Flash speed / latency N/A / N/A input / output No data
5 tests	Claude Sonnet 4.6 speed / latency 27 tok/s / 11925ms input / output No data	Gemini 3.5 Flash speed / latency N/A / N/A input / output No data
	Claude Sonnet 4.6 claude-sonnet-4-6 speed / latency No data input / output $0.288/M/$1.44/M	Gemini 3.5 Flash gemini-3.5-flash speed / latency No data input / output $0/M
	Claude Sonnet 4.6 claude-sonnet-4-6 speed / latency No data input / output $0/M/$0/M	Gemini 3.5 Flash gemini-3.5-flash speed / latency No data input / output $75.00/M
	Claude Sonnet 4.6 claude-sonnet-4-6 speed / latency No data input / output $0/request	Gemini 3.5 Flash gemini-3.5-flash speed / latency No data input / output $0/request

FAQ

Weighted outcome: Gemini 3.5 Flash. Benchmark capability categories carry 80%, while price, API performance, and availability carry 20%.

Why is this comparison indexable?: It has 4 verifiable comparison points, and both models have pricing or benchmark data.
Are missing metrics invented?: No. Metrics without LMSpeed data are omitted from this report.

Input

TextImagevideoFileAudio

Output

Text

Features	Text inputImage inputFile inputText outputTool callingStructured outputsJSON modeReasoning	Text inputImage inputFile inputAudio inputText outputTool callingStructured outputsJSON modeReasoning

50.3

Gemini 3.5 Flash54.6

Knowledge

Claude Sonnet 4.6 leads by 14.5

Claude Sonnet 4.670.6

Gemini 3.5 Flash56.1

Math

Gemini 3.5 Flash leads by 1.9

Claude Sonnet 4.653.2

Gemini 3.5 Flash55.1

Multilingual

No data

Claude Sonnet 4.6-

Gemini 3.5 Flash-

Multimodal

Gemini 3.5 Flash leads by 14.0

Claude Sonnet 4.644.5

Gemini 3.5 Flash58.5

Instruction following

Gemini 3.5 Flash leads by 11.5

Claude Sonnet 4.643.8

Gemini 3.5 Flash55.3

/

$0/M

/

$300.00/M

Comparison sheet

Model metadata

When to choose each model

Benchmark score comparison

Category performance

Agents

Coding

Reasoning

Professional benchmark details

BenchLM overall score

Output speed

Time to first answer token

Time to first token

Blended price

Input price

Output price

GPQA

HLE

CritPt

AA-LCR

CursorBench v3.1

Vibe Code Bench

BenchLM Coding score

SciCode

AA-SciCode

FrontierMath v2 (Tiers 1-3)

FrontierMath v2 (Tier 4)

BenchLM Math score

AA-Omniscience Accuracy

AA-HLE

AA-GPQA Diamond

Artificial Analysis Intelligence Index

BenchLM Knowledge score

AA-Omniscience Hallucination Rate

AA-MMMU-Pro

BenchLM Multimodal Grounded score

CharXiv

Design Arena Website

AA-IFBench

OSWorld-Verified

Gert Labs

Terminal-Bench 2.0

BenchLM Agentic score

τ²-bench results

API audit comparison

Provider examples

FAQ

Related compare reports

Knowledge

Math

Multilingual

Multimodal

Instruction following