The Known Good Updated 2 Sep 2026 Subscribe
Anthropic: Claude Opus 4.1 vs Google: Gemini 3.5 Flash ·Anthropic vs Google

Anthropic: Claude Opus 4.1 vs Google: Gemini 3.5 Flash — head-to-head comparison

Anthropic: Claude Opus 4.1 profile Google: Gemini 3.5 Flash profile All comparisons
Anthropic: Claude Opus 4.1 — Anthropic
Quality
#48 of 65
50based on 5 of 7 evaluations
Known Good Index
Speed
#331 of 339
7.5
Output tokens per second
Price
#427 of 439
$30.00
Blended per 1M tokens
In $15.00 · Out $75.00
Cache hit price
#316 of 322
$1.50
per 1M tokens (−90%)
Context
#297 of 473
200k
tokens (~300 pages)
Google: Gemini 3.5 Flash — Google
Quality
#3 of 65
95based on 3 of 7 evaluations
Known Good Index
Speed
#11 of 339
167.1
Output tokens per second
Price
#338 of 439
$3.38
Blended per 1M tokens
In $1.50 · Out $9.00
Cache hit price
#206 of 322
$0.15
per 1M tokens (−90%)
Context
#82 of 473
1.05M
tokens (~1,600 pages)
Summary

On the Known Good Index, Anthropic: Claude Opus 4.1 scores 50 and Google: Gemini 3.5 Flash scores 95 — a 45-point lead for Google: Gemini 3.5 Flash. They share 3 published evaluations, with Anthropic: Claude Opus 4.1 ahead on 0 and Google: Gemini 3.5 Flash ahead on 3.

Blended pricing is $30.00 per 1M tokens for Anthropic: Claude Opus 4.1 and $3.38 for Google: Gemini 3.5 Flash — Google: Gemini 3.5 Flash is about 8.9× cheaper.

Throughput is 8 tokens per second for Anthropic: Claude Opus 4.1 and 167 for Google: Gemini 3.5 Flash, with time to first token at 2.7s and 2.1s. Anthropic: Claude Opus 4.1 accepts 200k tokens of context against 1.05M.

Anthropic: Claude Opus 4.1 is proprietary; Google: Gemini 3.5 Flash is proprietary. 5 tracked hosts serve one or both, and 1 serve both.

Generated from tracked data on 3 Sep 2026 · how these comparisons are computed →

At a glance
MetricAnthropic: Claude Opus 4.1Google: Gemini 3.5 Flash
Known Good Index 50 based on 5 of 7 evaluations 95 based on 3 of 7 evaluations
Blended $/1M $30.00 $3.38
Output tok/s 8 167
Context window 200k 1.05M
Providers 4 2
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Quality

Known Good Index and the capability indices, side by side

Index scores

Each index is min-max normalised across tracked models and scaled 0–100 from published evaluations. We do not run these evaluations.

MetricAnthropic: Claude Opus 4.1Google: Gemini 3.5 Flash
Known Good Index 50 95
Coding Index 62
Reasoning Index 43
Openness Index 5 5
The Known Good

Quality Breakdown

Every evaluation both models report a published score for

Evaluations both models report

Bar = Anthropic: Claude Opus 4.1 · marker = Google: Gemini 3.5 Flash · scores ingested from Epoch AI (CC-BY 4.0)

GPQA Diamond73 / 93
Mock AIME 2024–2540 / 96
SWE-bench Verified73 / 79

Right-hand figures read Anthropic: Claude Opus 4.1 / Google: Gemini 3.5 Flash. Anthropic: Claude Opus 4.1 leads on 0 of 3, Google: Gemini 3.5 Flash on 3.

The Known Good

Arena Elo

Human preference rating from blind pairwise votes

Arena ratings

Elo from blind pairwise votes, ingested from Arena. Higher is better.

MetricAnthropic: Claude Opus 4.1Google: Gemini 3.5 Flash
Text Arena 1,418
Text Arena (style controlled) 1,448
The Known Good

Price & Cost

Published API pricing by token type

Published pricing

USD per 1M tokens. Blended is a 3:1 input:output mix. Live from OpenRouter, cross-checked against models.dev. Lower is better.

MetricAnthropic: Claude Opus 4.1Google: Gemini 3.5 Flash
Input $/1M $15.00 $1.50
Output $/1M $75.00 $9.00
Blended $/1M $30.00 $3.38
Cache read $/1M $1.500 $0.150
The Known Good
We publish blended price rather than cost-per-task. Cost-per-task requires token counts from an evaluation suite we do not run. Blended price is computed from published rates and is fully reproducible — see the pricing methodology.

Context Window

Maximum input accepted and maximum output emitted

Context and output limits

Provider-declared limits, from metadata via models.dev and OpenRouter. Higher is better.

MetricAnthropic: Claude Opus 4.1Google: Gemini 3.5 Flash
Context window 200k 1.05M
Max output tokens 32k 66k
The Known Good

Speed & Latency

Mean throughput and time to first token across hosting providers, over successful measurements from the last 48 hours

Throughput and latency

Means across all tracked providers over successful measurements from the last 48 hours, derived from OpenRouter endpoint telemetry.

MetricAnthropic: Claude Opus 4.1Google: Gemini 3.5 Flash
Output tokens/s 8 167
Time to first token 2.7s 2.1s
The Known Good

Providers

Which hosts serve each model, and at what price and speed

5 hosts · 1 serve both
Full provider benchmarks →
Provider Anthropic: Claude Opus 4.1 blendedAnthropic: Claude Opus 4.1 tok/s Google: Gemini 3.5 Flash blendedGoogle: Gemini 3.5 Flash tok/s
Amazon Bedrock · first party $30.00 11
Google · first party $30.00 3 $1.69 142
Anthropic · first party $30.00
Azure · first party $30.00
Google AI Studio $1.69 203

Per-host pricing and telemetry from OpenRouter. A dash means that host does not serve that model.

The Known Good
Sources for this page
Pricing & providers — OpenRouter Metadata — models.dev Benchmarks — Epoch AI (CC-BY 4.0)Elo — Arena Full attribution →