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AI model comparison

Gemini 3.1 Pro Preview Custom Tools vs GPT-5.1 Chat

Compare pricing, context limits, supported inputs and deployment options to choose a model for your workflow.

Gemini 3.1 Pro Preview Custom Tools from Google lists 1.05M context, 65.54K maximum output, $2.00 input per 1M tokens, $12.00 output per 1M tokens. GPT-5.1 Chat from OpenAI lists 128K context, 16.38K maximum output, $1.25 input per 1M tokens, $10.00 output per 1M tokens. Compare the inputs, outputs and deployment options below to see which fits your workflow.

Side-by-sideCapabilities and practical differences

Google

Gemini 3.1 Pro Preview Custom Tools

Gemini 3.1 Pro Preview Custom Tools from Google: Advanced Gemini model for complex reasoning, coding, and multimodal analysis.

Context
1.05M
Max output
65.54K
Input / 1M tokens
$2.00
Output / 1M tokens
$12.00

Accepts

  • Text input
  • Image input
  • Video input
  • Audio input
  • PDF input

Produces

  • Text output
Full model profilegithub.com ↗
VS

OpenAI

GPT-5.1 Chat

GPT-5.1 Chat from OpenAI: Chat-tuned GPT-5.1 for polished assistants, writing, and product conversations.

Context
128K
Max output
16.38K
Input / 1M tokens
$1.25
Output / 1M tokens
$10.00

Accepts

  • Text input
  • Image input

Produces

  • Text output
Full model profilegithub.com ↗

At a glance

Key differences

Compare the available figures below, then try both models on the work you need to do.

Gemini 3.1 Pro Preview Custom Tools

  • Context capacity: 1.05M
  • Maximum output: 65.54K

GPT-5.1 Chat

  • Input price: $1.25
  • Output price: $10.00

Context capacity

Higher listed limit

Gemini 3.1 Pro Preview Custom Tools:1.05M

GPT-5.1 Chat:128K

Gemini 3.1 Pro Preview Custom Tools

Maximum output

Higher listed limit

Gemini 3.1 Pro Preview Custom Tools:65.54K

GPT-5.1 Chat:16.38K

Gemini 3.1 Pro Preview Custom Tools

Input price

Lower listed token rate

Gemini 3.1 Pro Preview Custom Tools:$2.00

GPT-5.1 Chat:$1.25

GPT-5.1 Chat

Output price

Lower listed token rate

Gemini 3.1 Pro Preview Custom Tools:$12.00

GPT-5.1 Chat:$10.00

GPT-5.1 Chat

Specifications

Pricing, limits and capabilities

Specifications for Gemini 3.1 Pro Preview Custom Tools and GPT-5.1 Chat. Higher limits and lower prices describe these figures only.
SpecificationGemini 3.1 Pro Preview Custom ToolsGPT-5.1 Chat
ProviderGoogleOpenAI
Listed pricing routeGoogleOpenAI
Model familygemini-progpt-codex
Accepted inputstext, image, video, audio, pdftext, image
Produced outputstexttext
Context window1.05MHigher128K
Max output65.54KHigher16.38K
Input price / 1M$2.00$1.25Lower
Output price / 1M$12.00$10.00Lower
Reasoning modeDocumentedDocumented
Tool callingDocumentedDocumented
Image inputDocumentedDocumented
Audio inputDocumentedNot documented
Structured outputDocumentedDocumented
LicenseProprietaryProprietary

Workload guidance

Which model should you choose?

Consider Gemini 3.1 Pro Preview Custom Tools if you need larger context or larger maximum output. Consider GPT-5.1 Chat if you need a lower listed input rate or a lower listed output rate. Test both on the same representative examples and judge the output against your acceptance criteria. Include tool failures, retries and the time to a completed task.

Documentation and model profiles

Explore each model’s features, API requirements and licence terms in the sources below.

Questions people ask

It brings together documented inputs and outputs, token limits, deployment terms and available pricing. When both models have source-linked, verified results on a shared benchmark, those results are shown with their individual sources. The comparison is a starting point for evaluating your own workload.

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