GPTvsGemini

o3 Pro 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

o3 Pro

Flagship

Gemini 3.1 Pro Custom Tools

Mid-tier
Input $/MTok
$20.00
$2.00
Output $/MTok
$80.00
$12.00
Cache discount
0% off
90% off
Context
200K
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
o3 Pro
Gemini 3.1 Pro Custom Tools

Guidance

When to use o3 Pro vs Gemini 3.1 Pro Custom Tools

Choose o3 Pro when...

  • Similar performance; consider provider preference or ecosystem fit.

Choose Gemini 3.1 Pro Custom Tools when...

  • -Cost matters: 90% cheaper on input tokens
  • -You need a larger context window (1,048.576K vs 200K)

At scale

Cost at scale

Estimated cost assuming a seventy percent input and thirty percent output token split.
o3 Pro
Gemini 3.1 Pro Custom Tools
100K tokens
$3.80
$0.50Cheaper
1M tokens
$38.00
$8.20Cheaper
10M tokens
$380.00
$82.00Cheaper

FAQ

When should I use o3 Pro instead of Gemini 3.1 Pro Custom Tools?

o3 Pro 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 o3 Pro?

Yes. Gemini 3.1 Pro Custom Tools input costs $2.00/MTok vs $20.00/MTok for o3 Pro, saving 90% on input.

What are the context window sizes for o3 Pro and Gemini 3.1 Pro Custom Tools?

o3 Pro has a 200K 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.