Gemini 3.1 Pro Preview vs GPT-4o (08-06)

Gemini 3.1 Pro Preview (2026) and GPT-4o (08-06) (2024) are compact production models from Google DeepMind and OpenAI. Gemini 3.1 Pro Preview ships a 1m-token context window, while GPT-4o (08-06) ships a 128k-token context window. On MMLU PRO, Gemini 3.1 Pro Preview leads by 16.3 pts. This comparison covers specs, pricing, API access, capabilities, benchmarks, input and output token costs, and production fit for coding and agent workloads.

Gemini 3.1 Pro Preview fits 8x more tokens; pick it for long-context work and GPT-4o (08-06) for tighter calls.

Decision scorecard

Local evidence first
SignalGemini 3.1 Pro PreviewGPT-4o (08-06)
Best formultimodal apps, tool-calling agents, and long-context analysismultimodal apps and provider-routed production
Decision fitCoding, RAG, and AgentsCoding, RAG, and Agents
Context window1m128k
Cheapest output$12/1M tokens$10/1M tokens
Provider routes5 tracked3 tracked
Shared benchmarksMMLU PRO leader1 shared

Decision tradeoffs

Choose Gemini 3.1 Pro Preview when...
  • Gemini 3.1 Pro Preview holds a shared-benchmark lead on MMLU PRO, ahead by 16.3 points.
  • Gemini 3.1 Pro Preview has the larger context window for long prompts, retrieval packs, or transcript analysis.
  • Gemini 3.1 Pro Preview has broader tracked provider coverage for fallback and route flexibility.
  • Gemini 3.1 Pro Preview uniquely exposes JSON / Tool use in local model data.
  • Local decision data tags Gemini 3.1 Pro Preview for Coding, RAG, and Agents.
Choose GPT-4o (08-06) when...
  • GPT-4o (08-06) has the lower cheapest tracked output price at $10/1M tokens.
  • Local decision data tags GPT-4o (08-06) for Coding, RAG, and Agents.

Monthly cost at traffic

Estimate token spend from the cheapest tracked input and output route or tier on this page.

Lower estimate GPT-4o (08-06)

Gemini 3.1 Pro Preview

$4,600

Cheapest tracked route/tier: Google AI Studio

GPT-4o (08-06)

$4,500

Cheapest tracked route/tier: OpenAI API

Estimated monthly gap: $100. Batch, cache, alternate speed tiers, and negotiated pricing are excluded from this local estimate.

Switch friction

Gemini 3.1 Pro Preview -> GPT-4o (08-06)
  • Provider overlap exists on OpenRouter; start route-level A/B tests there.
  • GPT-4o (08-06) is $2/1M tokens lower on cheapest tracked output pricing before cache, batch, or negotiated discounts.
  • Check replacement coverage for JSON / Tool use before moving production traffic.
GPT-4o (08-06) -> Gemini 3.1 Pro Preview
  • Provider overlap exists on OpenRouter; start route-level A/B tests there.
  • Gemini 3.1 Pro Preview is $2/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
  • Gemini 3.1 Pro Preview adds JSON / Tool use in local capability data.

Specs

Specification
Released2026-02-192024-08-06
Context window1m128k
Parameters—1.76T (8x222B MoE)*
ArchitectureDecoder OnlyMixture of Experts
LicenseProprietaryProprietary
OpennessProprietaryProprietary
WeightsNot releasedNot released
CodeUnknownUnknown
Commercial useCommercial use: conditionalCommercial use: conditional
Knowledge cutoff2025-012023-10

Pricing and availability

Pricing attributeGemini 3.1 Pro PreviewGPT-4o (08-06)
Input price
0-200,001t
$2/1M tokens
200,001t+
$4/1M tokens
$2.50/1M tokens
Output price
0-200,001t
$12/1M tokens
200,001t+
$18/1M tokens
$10/1M tokens
Providers
Google AI StudioGCP Vertex AIOpenRouterReplicate APIVercel AI Gateway
OpenAI APISalesforce Einstein Generative AIOpenRouter

Capabilities

CapabilityGemini 3.1 Pro PreviewGPT-4o (08-06)
VisionYesYes
MultimodalYesYes
ReasoningNoNo
JSON / Tool useYesNo
Structured outputsYesYes
Code executionYesYes
IDE integrationNoNo
Computer useNoNo
Parallel agentsNoNo

Benchmarks

BenchmarkGemini 3.1 Pro PreviewGPT-4o (08-06)
MMLU PRO91.074.7

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Model pages
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Last reviewed: 2026-06-29. Data sourced from public model cards and provider documentation.