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Gemini 3.1 Pro vs Gemini 2.5 Pro

Pricing, context window, and benchmark comparison · Last updated April 2026

Quick Verdict

Gemini 2.5 Pro is cheaper than Gemini 3.1 Pro at $1.25/1M/1M vs $2.00/1M/1M input tokens — a 1.6x cost difference. Gemini 3.1 Pro scores higher on quality benchmarks (ELO 1410). Choose Gemini 2.5 Pro for cost-sensitive workloads; choose Gemini 3.1 Pro for maximum quality.

Detailed Comparison

MetricGemini 3.1 ProGemini 2.5 Pro
Input Price / 1M tokens$2.00/1M$1.25/1MCheaper
Output Price / 1M tokens$12.00/1M$10.00/1MCheaper
Context Window1M2MLarger
ELO Score (LMSYS)1410Smarter1385
Open Source
Free Tier
Release Date2026-032025-06

Which is cheaper: Gemini 3.1 Pro or Gemini 2.5 Pro?

Gemini 2.5 Pro is the cheaper option at $1.25/1M per 1M input tokens, compared to $2.00/1M for Gemini 3.1 Pro. That is a 1.6x cost difference on input tokens. Output pricing follows a similar pattern: Gemini 3.1 Pro charges $12.00/1M/1M vs $10.00/1M/1M for Gemini 2.5 Pro.

Which has better quality: Gemini 3.1 Pro or Gemini 2.5 Pro?

Based on LMSYS Chatbot Arena rankings, Gemini 3.1 Pro achieves a higher ELO score (1410 vs 1385), suggesting stronger performance on open-ended tasks. Gemini 3.1 Pro excels at google's latest flagship with major reasoning improvements. Gemini 2.5 Pro is known for 2m token context window — among the largest available.

Which should you choose: Gemini 3.1 Pro or Gemini 2.5 Pro?

Choose Gemini 3.1 Pro if:
  • Google's latest flagship with major reasoning improvements
  • 1M token context window
  • Native multimodal (text, image, video, audio)
Choose Gemini 2.5 Pro if:
  • 2M token context window — among the largest available
  • Strong multimodal reasoning across text, video, and audio
  • Excellent price-to-quality ratio vs. flagships

Frequently Asked Questions

Which is cheaper: Gemini 3.1 Pro or Gemini 2.5 Pro?

Gemini 2.5 Pro is cheaper at $1.25/1M per 1M input tokens, making it 1.6x more affordable.

Which has better quality: Gemini 3.1 Pro or Gemini 2.5 Pro?

Gemini 3.1 Pro scores higher on the LMSYS Chatbot Arena with an ELO of 1410, suggesting better overall quality for most tasks.

Which has a larger context window: Gemini 3.1 Pro or Gemini 2.5 Pro?

Gemini 2.5 Pro has a larger context window at 2000K tokens.

Should I choose Gemini 3.1 Pro or Gemini 2.5 Pro?

Choose Gemini 2.5 Pro if cost is the priority. Choose Gemini 3.1 Pro if benchmark quality is most important. Consider your specific use case: Gemini 3.1 Pro is best for reasoning and long-context, while Gemini 2.5 Pro excels at long-context and document-analysis.

Is Gemini 3.1 Pro or Gemini 2.5 Pro open source?

Gemini 3.1 Pro is proprietary. Gemini 2.5 Pro is proprietary.

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