The Known Good Updated 4 Sep 2026 Subscribe
Google: Gemini 2.5 Pro vs Google: Gemini 3 Flash Preview ·Google vs Google

Google: Gemini 2.5 Pro vs Google: Gemini 3 Flash Preview — head-to-head comparison

Google: Gemini 2.5 Pro profile Google: Gemini 3 Flash Preview profile All comparisons
Google: Gemini 2.5 Pro — Google
Quality
#38 of 65
65based on 4 of 7 evaluations
Known Good Index
Speed
#42 of 338
101.8
Output tokens per second
Price
#348 of 442
$3.44
Blended per 1M tokens
In $1.25 · Out $10.00
Cache hit price
#181 of 324
$0.12
per 1M tokens (−90%)
Context
#82 of 476
1.05M
tokens (~1,600 pages)
Google: Gemini 3 Flash Preview — Google
Quality
#16 of 65
83based on 4 of 7 evaluations
Known Good Index
Speed
#70 of 338
85.5
Output tokens per second
Price
#249 of 442
$1.12
Blended per 1M tokens
In $0.50 · Out $3.00
Cache hit price
#110 of 324
$0.050
per 1M tokens (−90%)
Context
#63 of 476
1.05M
tokens (~1,600 pages)
Summary

On the Known Good Index, Google: Gemini 2.5 Pro scores 65 and Google: Gemini 3 Flash Preview scores 83 — a 18-point lead for Google: Gemini 3 Flash Preview. They share 4 published evaluations, with Google: Gemini 2.5 Pro ahead on 0 and Google: Gemini 3 Flash Preview ahead on 4.

Blended pricing is $3.44 per 1M tokens for Google: Gemini 2.5 Pro and $1.12 for Google: Gemini 3 Flash Preview — Google: Gemini 3 Flash Preview is about 3.1× cheaper.

Throughput is 102 tokens per second for Google: Gemini 2.5 Pro and 86 for Google: Gemini 3 Flash Preview, with time to first token at 7.1s and 4.7s. Google: Gemini 2.5 Pro accepts 1.05M tokens of context against 1.05M.

Google: Gemini 2.5 Pro is proprietary; Google: Gemini 3 Flash Preview is proprietary. 2 tracked hosts serve one or both, and 2 serve both.

Generated from tracked data on 4 Sep 2026 · how these comparisons are computed →

At a glance
MetricGoogle: Gemini 2.5 ProGoogle: Gemini 3 Flash Preview
Known Good Index 65 based on 4 of 7 evaluations 83 based on 4 of 7 evaluations
Blended $/1M $3.44 $1.12
Output tok/s 102 86
Context window 1.05M 1.05M
Providers 2 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.

MetricGoogle: Gemini 2.5 ProGoogle: Gemini 3 Flash Preview
Known Good Index 65 83
Coding Index 43 72
Openness Index 5 5
The Known Good

Quality Breakdown

Every evaluation both models report a published score for

Evaluations both models report

Bar = Google: Gemini 2.5 Pro · marker = Google: Gemini 3 Flash Preview · scores ingested from Epoch AI (CC-BY 4.0)

GPQA Diamond85 / 89
Mock AIME 2024–2584 / 96
SWE-bench Verified58 / 75
Terminal-Bench33 / 51

Right-hand figures read Google: Gemini 2.5 Pro / Google: Gemini 3 Flash Preview. Google: Gemini 2.5 Pro leads on 0 of 4, Google: Gemini 3 Flash Preview on 4.

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.

MetricGoogle: Gemini 2.5 ProGoogle: Gemini 3 Flash Preview
Text Arena 1,458
Text Arena (style controlled) 1,446
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.

MetricGoogle: Gemini 2.5 ProGoogle: Gemini 3 Flash Preview
Input $/1M $1.25 $0.50
Output $/1M $10.00 $3.00
Blended $/1M $3.44 $1.12
Cache read $/1M $0.125 $0.050
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.

MetricGoogle: Gemini 2.5 ProGoogle: Gemini 3 Flash Preview
Context window 1.05M 1.05M
Max output tokens 66k 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.

MetricGoogle: Gemini 2.5 ProGoogle: Gemini 3 Flash Preview
Output tokens/s 102 86
Time to first token 7.1s 4.7s
The Known Good

Providers

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

2 hosts · 2 serve both
Full provider benchmarks →
Provider Google: Gemini 2.5 Pro blendedGoogle: Gemini 2.5 Pro tok/s Google: Gemini 3 Flash Preview blendedGoogle: Gemini 3 Flash Preview tok/s
Google · first party $3.44 107 $0.56 66
Google AI Studio $1.72 103 $0.56 72

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 →