Head-to-head

GPT-5.5 vs Gemini 3.1 Pro

How GPT-5.5 (OpenAI) and Gemini 3.1 Pro (Google) compare on price, context window and best-fit use case.

In short: GPT-5.5 is best for highest-stakes reasoning, complex agents, and frontier coding tasks where capability outweighs cost, while Gemini 3.1 Pro suits long-document and multimodal workloads, RAG over huge corpora, and Google Cloud-native apps. On price it's $5.00 vs $2.00 (under 200K; $4.00 above) per 1M input tokens; on context, ~1.05M tokens (128K max output) vs 2M tokens.

Verdict

GPT-5.5 is the more capable pick (Bq score 95 vs 92). Choose Gemini 3.1 Pro if budget leads: its input price is $2.00 (under 200K; $4.00 above) per 1M vs $5.00.

SpecGPT-5.5Gemini 3.1 Pro
DeveloperOpenAIGoogle
Context window~1.05M tokens (128K max output)2M tokens
Input price /1M$5.00$2.00 (under 200K; $4.00 above)
Output price /1M$30.00$12.00 (under 200K; $18.00 above)
Modalitiestext, imagetext, image, audio, video
Best forHighest-stakes reasoning, complex agents, and frontier coding tasks where capability outweighs cost.Long-document and multimodal workloads, RAG over huge corpora, and Google Cloud-native apps.

GPT-5.5

  • State-of-the-art reasoning and agentic workflows
  • 1M+ context window
  • Strong coding and tool use
  • Multimodal (text + image input)
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Gemini 3.1 Pro

  • Largest mainstream context (2M)
  • Strong multimodal reasoning
  • Native Google ecosystem integration
  • Competitive pricing
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