LLM Reference

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 procurement flexibility.
  • Gemini 3.1 Pro Preview uniquely exposes Function calling and 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 Function calling and 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 Function calling and 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
Function callingYesNo
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

Deep dive

On shared benchmark coverage, MMLU PRO has Gemini 3.1 Pro Preview at 91.0 and GPT-4o (08-06) at 74.7, with Gemini 3.1 Pro Preview ahead by 16.3 points. The largest visible gap is 16.3 points on MMLU PRO, which matters most when that benchmark mirrors your workload. Treat isolated benchmark wins as directional, because provider routing, prompt style, and tool access can move real application results.

The capability footprint differs most on function calling: Gemini 3.1 Pro Preview and tool use: Gemini 3.1 Pro Preview. Both models share vision, multimodal input, structured outputs, and code execution, so the practical split is not just feature count. Use those differences to decide whether the page is about raw model quality, agentic coding support, multimodal ingestion, or predictable structured API behavior.

For cost, Gemini 3.1 Pro Preview lists tiered pricing: 0-200,001t is $2/1M input and $12/1M output; 200,001t+ is $4/1M input and $18/1M output, while GPT-4o (08-06) lists $2.50/1M input and $10/1M output tokens on the cheapest tracked provider. A 70/30 input-output blend puts GPT-4o (08-06) lower by about $0.25 per million blended tokens. For tiered rows, this cheapest-track view can understate interactive or fast-lane spend, so compare the tier you will actually use. Availability is 5 providers versus 3, so concentration risk also matters.

Choose Gemini 3.1 Pro Preview when coding workflow support, larger context windows, and lower cheapest-tier input-token cost are central to the workload. Choose GPT-4o (08-06) when coding workflow support are more important. For production, rerun your own prompts through the exact provider, region, and tool stack you plan to ship.

FAQ

Which has a larger context window, Gemini 3.1 Pro Preview or GPT-4o (08-06)?

Gemini 3.1 Pro Preview supports 1m tokens, while GPT-4o (08-06) supports 128k tokens. That gap matters most for long documents, large codebases, retrieval-heavy agents, and conversations where earlier context must remain visible.

Which is cheaper, Gemini 3.1 Pro Preview or GPT-4o (08-06)?

Gemini 3.1 Pro Preview lists tiered pricing: 0-200,001t is $2/1M input and $12/1M output; 200,001t+ is $4/1M input and $18/1M output. GPT-4o (08-06) lists $2.50/1M input and $10/1M output tokens on the cheapest tracked provider. Compare the tier you will actually use; cheap async pricing can overstate savings for interactive workflows. Provider discounts or batch pricing can still change the final bill.

Is Gemini 3.1 Pro Preview or GPT-4o (08-06) open source?

Gemini 3.1 Pro Preview is listed under Proprietary. GPT-4o (08-06) is listed under Proprietary. License labels affect whether you can self-host, redistribute weights, or rely only on hosted APIs, so confirm the upstream license before deployment.

Which is better for vision, Gemini 3.1 Pro Preview or GPT-4o (08-06)?

Both Gemini 3.1 Pro Preview and GPT-4o (08-06) expose vision. The better choice depends on benchmark fit, context budget, pricing, and whether your provider route exposes the same capability surface.

Which is better for multimodal input, Gemini 3.1 Pro Preview or GPT-4o (08-06)?

Both Gemini 3.1 Pro Preview and GPT-4o (08-06) expose multimodal input. The better choice depends on benchmark fit, context budget, pricing, and whether your provider route exposes the same capability surface.

Where can I run Gemini 3.1 Pro Preview and GPT-4o (08-06)?

Gemini 3.1 Pro Preview is available on Google AI Studio, GCP Vertex AI, OpenRouter, Replicate API, and Vercel AI Gateway. GPT-4o (08-06) is available on OpenAI API, Salesforce Einstein Generative AI, and OpenRouter. Provider coverage can affect latency, region availability, compliance posture, and fallback options.

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