Head-to-head comparison

Claude Opus 4.8 vs. Gemini 3.5 Flash

Compare published benchmark results from matching versions and cohorts, API pricing, and technical specifications. Any documented test setup differences remain visible.

shared result series: 29
distinct benchmarks: 29
latest retrieval: 2026-09-29

First modelSecond model

Specifications

General specifications

Release date, availability, context window, architecture, and published parameter counts at a glance. Undisclosed details remain marked as unavailable.

Specifications for Claude Opus 4.8 and Gemini 3.5 Flash
Attribute	Claude Opus 4.8	Gemini 3.5 Flash
Provider	Anthropic	Google
Released	May 2026	May 19, 2026
Availability	Legacy	Active
Model type	Proprietary	Proprietary
Parameters	Not published	Not published
Architecture	Not published	Not published
Context window	1,000,000 tokens	1,048,576 tokens
Knowledge cutoff	January 2026	Not published
Technical sources	Model, Knowledge cutoff	Model

Pricing

API pricing compared

The table compares official standard API rates per 1M tokens, including published cache pricing. Batch, fast, priority, regional surcharges, tool calls, and cloud platform pricing are excluded.

API pricing for Claude Opus 4.8 and Gemini 3.5 Flash
Price type	Claude Opus 4.8	Gemini 3.5 Flash
API input	$5	$1.5
API output	$25	$9
Cache read	$0.5	$0.15
Cache write (5 min.)	$6.25	Not listed
Cache write (1 hr.)	$10	Not listed
Price verified	09/22/2026 Source	09/22/2026 Source

Claude Opus 4.8Gemini 3.5 Flash

API inputUSD per 1M tokens, base tier

Claude Opus 4.8$5

Gemini 3.5 Flash$1.5

API outputUSD per 1M tokens, base tier

Claude Opus 4.8$25

Gemini 3.5 Flash$9

Cache readUSD per 1M tokens, base tier

Claude Opus 4.8$0.5

Gemini 3.5 Flash$0.15

Key to the marks:better valuebetter, but not conclusivetie

Pricing by provider

Direct developer pricing and provider endpoint tariffs routed through OpenRouter are listed separately. Prices are in USD per 1M tokens. Context-dependent direct tiers plus regional, Flex, Priority, and other OpenRouter tariffs remain individually identifiable.

No provider tariff for Claude Opus 4.8 is available in the stored OpenRouter snapshot. The official direct price is still shown.

Provider pricing for Claude Opus 4.8 and Gemini 3.5 Flash
Model	Provider	Purchase route and tariff	Input per 1M tokens	Output per 1M tokens	Source
Claude Opus 4.8	Anthropic	Direct from developerStandard API	Lowest listed price: $5	Lowest listed price: $25	Source09/22/2026
Gemini 3.5 Flash	Google	Direct from developerStandard API	$1.5	$9	Source09/22/2026
	Google	Via OpenRoutergoogle-vertex/global	$1.5	$9	Source10/15/2026
	Google	Via OpenRoutergoogle-vertex/global/flex	Lowest listed price: $0.75	Lowest listed price: $4.5	Source10/15/2026
	Google	Via OpenRoutergoogle-vertex/global/priority	$2.7	$16.2	Source10/15/2026
	Google	Via OpenRoutergoogle-vertex/us	$1.65	$9.9	Source10/15/2026
	Google AI Studio	Via OpenRoutergoogle-ai-studio	$1.5	$9	Source10/15/2026
	Google AI Studio	Via OpenRoutergoogle-ai-studio/flex	Lowest listed price: $0.75	Lowest listed price: $4.5	Source10/15/2026
	Google AI Studio	Via OpenRoutergoogle-ai-studio/priority	$2.7	$16.2	Source10/15/2026

Performance

Shared benchmarks

Only published results with the same benchmark version, task, metric, and comparison cohort are paired. Different reasoning levels, agents, harnesses, or output limits appear directly in the table.

Capability profile from matched benchmarks

Each axis averages directly matched benchmark families. A value of 100 means the stronger value within this pair, not a universal quality score.

Claude Opus 4.8

Gemini 3.5 Flash

Coding: 100 / 54.9 (6 benchmark families)

Reasoning: 99.7 / 100 (1 benchmark family)

Knowledge: 100 / 99.9 (1 benchmark family)

Finance: 98.9 / 94.5 (6 benchmark families)

Legal: 100 / 65.5 (3 benchmark families)

Agentic tasks: 99.2 / 93.6 (2 benchmark families)

Multimodal: 98.1 / 100 (1 benchmark family)

Productivity: 100 / 87.3 (1 benchmark family)

28 matched rows from 26 benchmark families were considered. The radar shows 8 of 12 comparable categories.

Claude Opus 4.8Gemini 3.5 Flash

Code MigrationOverall. Higher is better. No documented setup difference

Claude Opus 4.847.25 %

Gemini 3.5 Flash26.745 %

CorpFin v2Overall. Higher is better. No documented setup difference

Claude Opus 4.866.706 %

Gemini 3.5 Flash64.686 %

EMBOverall. Higher is better. No documented setup difference

Claude Opus 4.869.373 %

Gemini 3.5 Flash63.548 %

EnigmaEvalOverall. Higher is better. Test setup not documented as identical

Claude Opus 4.823.51% ± 2.41

Gemini 3.5 Flash25.41% ± 2.45

Finance Agent (v2)Overall. Higher is better. No documented setup difference

Claude Opus 4.853.918 %

Gemini 3.5 Flash57.861 %

GPQA DiamondOverall. Higher is better. No documented setup difference

Claude Opus 4.892.424 %

Gemini 3.5 Flash92.676 %

Harvey's Legal Agent BenchmarkOverall · Task fully resolved. Higher is better. No documented setup difference

Claude Opus 4.89.583 %

Gemini 3.5 Flash2.5 %

Legal Research BenchOverall · All-pass. Higher is better. No documented setup difference

Claude Opus 4.843.75 %

Gemini 3.5 Flash30.769 %

LegalBenchOverall. Higher is better. No documented setup difference

Claude Opus 4.883.568 %

Gemini 3.5 Flash83.602 %

LiveCodeBench v6Overall. Higher is better. No documented setup difference

Claude Opus 4.887.819 %

Gemini 3.5 Flash87.604 %

MedCodeOverall. Higher is better. No documented setup difference

Claude Opus 4.853.217 %

Gemini 3.5 Flash55.825 %

MedScribeOverall. Higher is better. No documented setup difference

Claude Opus 4.885.755 %

Gemini 3.5 Flash76.574 %

Key to the marks:better valuebetter, but not conclusivetie

Benchmark scores for Claude Opus 4.8 and Gemini 3.5 Flash
Benchmark and task	Claude Opus 4.8	Gemini 3.5 Flash	Source
Code MigrationOverall Test details No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is better	Winner47.25 %	26.745 %	Vals AI Source details Data as of: 09/27/2026
CorpFin v2Overall Test details No documented difference in the test setupVersion: 2Metric: accuracyScoring: Higher is better	Winner66.706 %	64.686 %	Vals AI Source details Data as of: 08/12/2026
EMBOverall Test details No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is better	Winner69.373 %	63.548 %	Vals AI Source details Data as of: 09/27/2026
EnigmaEvalOverall Test details Test setup not documented as identicalNo direct winnerVersion: open-source release 2026-07-23Metric: pass@1 accuracyScoring: Higher is betterClaude Opus 4.8: Snapshot: claude-opus-4.8-xhigh, Reasoning: xhigh, Attempts: pass@1 Gemini 3.5 Flash: Snapshot: gemini-3.5-flash-high, Reasoning: high, Attempts: pass@1Complex multimodal puzzles with exact answer matching and one attempt.	23.51% ± 2.41 95% confidence interval: ±2.41	Higher measured value25.41% ± 2.45 95% confidence interval: ±2.45	Scale AI Source details Data as of: 07/23/2026
Finance Agent (v2)Overall Test details No documented difference in the test setupVersion: 2Metric: accuracyScoring: Higher is better	53.918 %	Winner57.861 %	Vals AI Source details Data as of: 09/27/2026
GPQA DiamondOverall Test details No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is better	92.424 %	Winner92.676 %	Vals AI Source details Data as of: 09/01/2026
Harvey's Legal Agent BenchmarkOverall · Task fully resolved Test details No documented difference in the test setupVersion: 1Metric: task resolution rateScoring: Higher is better	Winner9.583 %	2.5 %	Vals AI Source details Data as of: 09/27/2026
Legal Research BenchOverall · All-pass Test details No documented difference in the test setupVersion: 1Metric: all-pass rateScoring: Higher is better	Winner43.75 %	30.769 %	Vals AI Source details Data as of: 09/27/2026
LegalBenchOverall Test details No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is better	83.568 %	Winner83.602 %	Vals AI Source details Data as of: 09/27/2026
LiveCodeBench v6Overall Test details No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is better	Winner87.819 %	87.604 %	Vals AI Source details Data as of: 09/01/2026
MedCodeOverall Test details No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is better	53.217 %	Winner55.825 %	Vals AI Source details Data as of: 09/26/2026
MedScribeOverall Test details No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is better	Winner85.755 %	76.574 %	Vals AI Source details Data as of: 09/26/2026
MMLU-ProOverall Test details No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is better	Winner89.585 %	89.515 %	Vals AI Source details Data as of: 09/01/2026
MMMU-ProOverall Test details No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is better	86.59 %	Winner88.266 %	Vals AI Source details Data as of: 09/01/2026
MortgageTaxOverall Test details No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is better	Winner69.912 %	68.124 %	Vals AI Source details Data as of: 09/01/2026
ProgramBenchOverall Test details No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is better	Winner1 %	0 %	Vals AI Source details Data as of: 09/27/2026
Public Benefits Bench v1.1Overall Test details No documented difference in the test setupVersion: 1.1Metric: accuracyScoring: Higher is better	Winner68.133 %	59.472 %	Vals AI Source details Data as of: 09/27/2026
SAGEOverall Test details No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is better	Winner54.788 %	49.885 %	Vals AI Source details Data as of: 09/26/2026
SkillsBenchOverall Test details No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is betterSettings: Harness: OpenHands	Winner59.227 %	52.737 %	Vals AI Source details Data as of: 09/27/2026
SWE-bench VerifiedOverall Test details No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is better	Winner88.6 %	78.8 %	Vals AI Source details Data as of: 09/01/2026
Tax Agent BenchOverall Test details No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is better	Winner64.906 %	53.526 %	Vals AI Source details Data as of: 09/27/2026
TaxEval v2Overall Test details No documented difference in the test setupVersion: 2Metric: accuracyScoring: Higher is better	Winner75.634 %	74.366 %	Vals AI Source details Data as of: 09/01/2026
Terminal-Bench 2.0Overall Test details No documented difference in the test setupVersion: 2.0Metric: accuracyScoring: Higher is better	Winner70.037 %	67.416 %	Vals AI Source details Data as of: 06/04/2026
Terminal-Bench 2.1Overall Test details No documented difference in the test setupVersion: 2.1Metric: accuracyScoring: Higher is better	71.91 %	Winner74.157 %	Vals AI Source details Data as of: 09/27/2026
Terminal-Bench 4.0Overall Test details No documented difference in the test setupVersion: 4.0Metric: accuracyScoring: Higher is better	Winner16.162 %	4.04 %	Vals AI Source details Data as of: 09/27/2026
Terminal-Bench ScienceOverall Test details No documented difference in the test setupVersion: 0.1Metric: accuracyScoring: Higher is better	Winner10 %	4.286 %	Vals AI Source details Data as of: 09/27/2026
Vals IndexOverall Test details No documented difference in the test setupVersion: 2Metric: weighted index scoreScoring: Higher is better	Winner60.908 %	53.079 %	Vals AI Source details Data as of: 09/27/2026
Vals Multimodal IndexOverall Test details No documented difference in the test setupVersion: 1.2Metric: weighted index scoreScoring: Higher is better	Winner70.889 %	62.928 %	Vals AI Source details Data as of: 08/11/2026
Vibe Code Bench v1.1Overall Test details No documented difference in the test setupVersion: 1.1Metric: accuracyScoring: Higher is betterSettings: Harness: OpenHands	Winner82.725 %	48.683 %	Vals AI Source details Data as of: 09/27/2026
Key to the marks:better valuebetter, but not conclusivetie

Our model tests

Our tests

SVG short test

One SVG prompt and fixed output settings. Captures are shown only with 0 reported reasoning tokens or documented lack of reasoning controls. Identical test conditions do not make the models' internal compute identical.

Shared test round: 4ae5d8eeb9a9

Claude Opus 4.8

Unavailable in this round

Gemini 3.5 Flash

Unavailable in this round

Earlier tests

Pelican on a bicycle

A community classic for free-form SVG drawing.

Claude Opus 4.8

Reasoning (requested): high

Current attempt

Run date: Oct 1, 2026
API provider: openrouter
Requested API model: anthropic/claude-opus-4.8
API model reported in response: anthropic/claude-opus-4.8
Reasoning setting: high
Pinned endpoint: Anthropic | anthropic/claude-4.8-opus-20260528
Temperature: Provider default
Token limit including reasoning: 8,192 tokens
Test protocol: community-visual-tests-v1
Technical checks: Passed, not a quality rating
Response time: 18 s

Visually reviewed. This individual test does not establish overall model quality.

Gemini 3.5 Flash

The response reached the token limit. No complete recording is available.

Reasoning (requested): high

Current attempt

Run date: Oct 6, 2026
API provider: openrouter
Requested API model: google/gemini-3.5-flash
API model reported in response: google/gemini-3.5-flash
Reasoning setting: high
Pinned endpoint: Google AI Studio | google/gemini-3.5-flash-20260519
Temperature: Provider default
Token limit including reasoning: 8,192 tokens
Test protocol: community-visual-tests-v1
Technical checks: Failed
Response time: 31.7 s

Not yet visually reviewed. A successful recording does not confirm correct physics or full compliance with the prompt.

Earlier attempts (3)

Oct 2, 2026API request failedReasoning setting: high
Oct 1, 2026API request failedReasoning setting: high
Sep 7, 2026API request failedReasoning setting: high

Prompt and test conditions

Generate an SVG of a pelican riding a bicycle

Token limit including reasoning: 8,192 tokens

Task origin (Simon Willison)

How to read this comparison

Winning one benchmark is not an overall verdict

Your workload, budget, and required context length matter most. A coding benchmark says little about visual understanding or agent performance.

The standard price table uses direct developer rates. The provider comparison labels OpenRouter endpoints, regions, and special tariffs separately.

Every result links to its measurement source and retrieval date. Labels distinguish vendor reports, official benchmark leaderboards, and independent evaluations. Disputed or archived results are excluded.

More matchups

Compare Claude Opus 4.8 and Gemini 3.5 Flash with other leading models using the same data and benchmark logic.

View the complete LLM comparison

Claude Opus 4.8 vs. Gemini 3.5 Flash

Change model selection

General specifications

API pricing compared

Shared benchmarks

Capability profile from matched benchmarks

Our tests

SVG short test

Claude Opus 4.8

Gemini 3.5 Flash

Pelican on a bicycle

Winning one benchmark is not an overall verdict

Related LLM comparisons