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GPTvsGemini

GPT 5 Mini 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

GPT 5 Mini

Fast / Budget

Gemini 3.1 Pro Custom Tools

Mid-tier
Input $/MTok
$0.25
$2.00
Output $/MTok
$2.00
$12.00
Cache discount
90% off
90% off
Context
272K
1,048.576K

Quality

Task confidence comparison

Confidence score from zero to one hundred by task type, where higher is better.
Code Generation
0
vs
0
Code Review
0
vs
0
Summarization
0
vs
0
Q&A
0
vs
0
Extraction
0
vs
0
Reasoning
0
vs
0
Classification
0
vs
0
Creative Writing
0
vs
0
GPT 5 Mini
Gemini 3.1 Pro Custom Tools

Guidance

When to use GPT 5 Mini vs Gemini 3.1 Pro Custom Tools

Choose GPT 5 Mini when...

  • -Cost matters: 88% cheaper on input tokens

Choose Gemini 3.1 Pro Custom Tools when...

  • -You need a larger context window (1,048.576K vs 272K)
  • 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.
GPT 5 Mini
Gemini 3.1 Pro Custom Tools
100K tokens
$0.08Cheaper
$0.50
1M tokens
$0.77Cheaper
$8.20
10M tokens
$7.75Cheaper
$82.00

FAQ

When should I use GPT 5 Mini instead of Gemini 3.1 Pro Custom Tools?

GPT 5 Mini 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 GPT 5 Mini?

Gemini 3.1 Pro Custom Tools input costs $2.00/MTok, which is 700% more than GPT 5 Mini at $0.25/MTok.

What are the context window sizes for GPT 5 Mini and Gemini 3.1 Pro Custom Tools?

GPT 5 Mini has a 272K token context window. Gemini 3.1 Pro Custom Tools has a 1,048.576K token context window.

Go deeper on either model

Per-call cost calculators, provider lineups, and price history for both models on this page.

GPT 5 Mini pricing & benchmarks

$0.25 / $2.00 per MTok

GPT 5 Mini cost calculator

All GPT models

GPT 5 Mini pricing history

Gemini 3.1 Pro Custom Tools pricing & benchmarks

$2.00 / $12.00 per MTok

Gemini 3.1 Pro Custom Tools cost calculator

All Gemini models

Gemini 3.1 Pro Custom Tools pricing history

Other comparisons

How GPT 5 Mini and Gemini 3.1 Pro Custom Tools stack up against the rest of the field.

GPT 5 Mini vs Claude Opus 4.8

GPT 5 Mini vs Claude Sonnet 4.6

GPT 5 Mini vs Claude Haiku 4.5

Gemini 3.1 Pro Custom Tools vs Claude Opus 4.8

Gemini 3.1 Pro Custom Tools vs Claude Sonnet 4.6

Gemini 3.1 Pro Custom Tools vs Claude Haiku 4.5

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

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