Gemini 3.1 ProvsGemini 3.5 Flash

Gemini 3.1 Pro
Gemini 3.5 Flash
API pricingUSD per 1M tokens · lower wins · base tier
Input price
$2.00$1.50
Output price
$12.00$9.00
Cached input price
$0.20$0.15
Benchmarks
BullshitBench v2
37%20%
Gray Swan IPI · k = 1
14.2%14.1%
Gray Swan IPI · k = 10
45.7%54.2%
Gray Swan IPI · k = 15
49.2%60.5%
SWE-Bench Pro
54.2%55.1%
DeepSWE 1.1
12%37%
MLE-Bench
42.6%49.7%
Terminal-Bench 2.1
70.3%76.2%
MCP Atlas
78.2%83.6%
Toolathlon
48.8%56.5%
Humanity's Last Exam · no tools
44.4%40.2%
ARC-AGI-2
77.1%72.1%
OSWorld-Verified
76.2%78.4%
Finance Agent v2
43%57.9%
GDPval-AA
13141656
GDPval-AA v2
9651349
CharXiv Reasoning
83.3%84.2%
MMMU-Pro
80.5%83.6%
Blueprint-Bench 2
26.5%33.6%
MRCR v2 (8-needle) · 128k average
84.9%77.3%
MRCR v2 (8-needle) · 1M pointwise
26.3%26.6%
Arena Elo (Text)
14851476
Arena Elo (Code)
14451499
BenchmarksPublished by one model only
SWE-Bench Verified
80.6%
CursorBench v3.2
48.8%
CursorBench v3.1
49.8%
Next.js Evals
75%
Terminal-Bench 2.0
68.5%
BU Bench
58%
BrowseComp
85.9%
Humanity's Last Exam · with tools
51.4%
FrontierMath · Tier 1–3
36.9%
FrontierMath · Tier 4
16.7%
GPQA Diamond
94.3%
GDPval (win/tie rate)
67.3%
Overview
CompanyGoogleGoogle
Release dateFeb 19 2026May 19 2026
AccessProprietaryProprietary

Which is better: Gemini 3.1 Pro or Gemini 3.5 Flash?

Gemini 3.5 Flash leads Gemini 3.1 Pro on 16 of the 23 benchmarks they both report. Gemini 3.5 Flash is cheaper on both input and output: $1.50 vs $2.00 per million input tokens, and $9.00 vs $12.00 per million output tokens. Figures are base-tier rates. Gemini 3.1 Pro shipped 89 days before Gemini 3.5 Flash, so benchmark comparisons should account for the intervening progress.

Published specifications for these two models are limited — see each model page for the latest details.

On BullshitBench v2, Gemini 3.1 Pro leads at 37% vs Gemini 3.5 Flash at 20%. On Gray Swan IPI · k = 1, Gemini 3.5 Flash leads at 14.1% vs Gemini 3.1 Pro at 14.2%. On Gray Swan IPI · k = 10, Gemini 3.1 Pro leads at 45.7% vs Gemini 3.5 Flash at 54.2%. On Gray Swan IPI · k = 15, Gemini 3.1 Pro leads at 49.2% vs Gemini 3.5 Flash at 60.5%. On SWE-Bench Pro, Gemini 3.5 Flash leads at 55.1% vs Gemini 3.1 Pro at 54.2%. On DeepSWE 1.1, Gemini 3.5 Flash leads at 37% vs Gemini 3.1 Pro at 12%. On MLE-Bench, Gemini 3.5 Flash leads at 49.7% vs Gemini 3.1 Pro at 42.6%. On Terminal-Bench 2.1, Gemini 3.5 Flash leads at 76.2% vs Gemini 3.1 Pro at 70.3%. On MCP Atlas, Gemini 3.5 Flash leads at 83.6% vs Gemini 3.1 Pro at 78.2%. On Toolathlon, Gemini 3.5 Flash leads at 56.5% vs Gemini 3.1 Pro at 48.8%. On Humanity's Last Exam · no tools, Gemini 3.1 Pro leads at 44.4% vs Gemini 3.5 Flash at 40.2%. On ARC-AGI-2, Gemini 3.1 Pro leads at 77.1% vs Gemini 3.5 Flash at 72.1%. On OSWorld-Verified, Gemini 3.5 Flash leads at 78.4% vs Gemini 3.1 Pro at 76.2%. On Finance Agent v2, Gemini 3.5 Flash leads at 57.9% vs Gemini 3.1 Pro at 43%. On GDPval-AA, Gemini 3.5 Flash leads at 1656 vs Gemini 3.1 Pro at 1314. On GDPval-AA v2, Gemini 3.5 Flash leads at 1349 vs Gemini 3.1 Pro at 965. On CharXiv Reasoning, Gemini 3.5 Flash leads at 84.2% vs Gemini 3.1 Pro at 83.3%. On MMMU-Pro, Gemini 3.5 Flash leads at 83.6% vs Gemini 3.1 Pro at 80.5%. On Blueprint-Bench 2, Gemini 3.5 Flash leads at 33.6% vs Gemini 3.1 Pro at 26.5%. On MRCR v2 (8-needle) · 128k average, Gemini 3.1 Pro leads at 84.9% vs Gemini 3.5 Flash at 77.3%. On MRCR v2 (8-needle) · 1M pointwise, Gemini 3.5 Flash leads at 26.6% vs Gemini 3.1 Pro at 26.3%. On Arena Elo (Text), Gemini 3.1 Pro leads at 1485 vs Gemini 3.5 Flash at 1476. On Arena Elo (Code), Gemini 3.5 Flash leads at 1499 vs Gemini 3.1 Pro at 1445.

Frequently asked questions

Gemini 3.1 Pro was released by Google on Feb 19 2026.

Gemini 3.5 Flash was released by Google on May 19 2026.

Gemini 3.5 Flash leads on SWE-Bench Pro — Gemini 3.1 Pro 54.2% vs Gemini 3.5 Flash 55.1%.

Gemini 3.1 Pro leads on Humanity's Last Exam · no tools — Gemini 3.1 Pro 44.4% vs Gemini 3.5 Flash 40.2%.

Gemini 3.5 Flash is cheaper on both input and output: $1.50 vs $2.00 per million input tokens, and $9.00 vs $12.00 per million output tokens. Figures are base-tier rates. Rates are pay-as-you-go API prices verified on August 18, 2026.

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