GeminivsGemini

Gemini 3 Flash vs Gemini 3.1 Pro Custom Tools

Side-by-side comparison of pricing, task quality, and projected cost at higher scale.

Pricing

Side-by-side pricing

Gemini 3 Flash

Fast / Budget

Gemini 3.1 Pro Custom Tools

Mid-tier
Input $/MTok
$0.50
$2.00
Output $/MTok
$3.00
$12.00
Cache discount
90% off
90% off
Context
1,048.576K
1,048.576K

Quality

Task confidence comparison

Confidence score from zero to one hundred by task type, where higher is better.
Code Generation
65
vs
0
Code Review
62
vs
0
Summarization
83
vs
0
Q&A
82
vs
0
Extraction
86
vs
0
Reasoning
58
vs
0
Classification
88
vs
0
Creative Writing
52
vs
0
Gemini 3 Flash
Gemini 3.1 Pro Custom Tools

Guidance

When to use Gemini 3 Flash vs Gemini 3.1 Pro Custom Tools

Choose Gemini 3 Flash when...

  • -Cost matters: 75% cheaper on input tokens

Choose Gemini 3.1 Pro Custom Tools when...

  • Similar performance; consider provider preference or ecosystem fit.

At scale

Cost at scale

Estimated cost assuming a seventy percent input and thirty percent output token split.
Gemini 3 Flash
Gemini 3.1 Pro Custom Tools
100K tokens
$0.13Cheaper
$0.50
1M tokens
$1.25Cheaper
$8.20
10M tokens
$12.50Cheaper
$82.00

FAQ

When should I use Gemini 3 Flash instead of Gemini 3.1 Pro Custom Tools?

Gemini 3 Flash and Gemini 3.1 Pro Custom Tools perform similarly across all tracked tasks. Pick based on pricing and provider preference.

Is Gemini 3.1 Pro Custom Tools cheaper than Gemini 3 Flash?

Gemini 3.1 Pro Custom Tools input costs $2.00/MTok, which is 300% more than Gemini 3 Flash at $0.50/MTok.

What are the context window sizes for Gemini 3 Flash and Gemini 3.1 Pro Custom Tools?

Gemini 3 Flash has a 1,048.576K token context window. Gemini 3.1 Pro Custom Tools has a 1,048.576K token context window.

Track your real costs

Comparisons show estimated costs at list price. The dashboard reveals your real spend and savings.