FlagshipOpenAI

GPT-5.1

GPT-5.1 is OpenAI's flagship multimodal model with 256K token context, supporting text and image inputs for complex reasoning and code generation tasks.

Context 256K
Tier Flagship
Knowledge Mar 2025
Tools Supported
Modalities text, image
Input from
$0.250 / 1M tokens
across 2 providers
Compare Prices

API Pricing

Cheapest on Microsoft Azure — 67% below avg
ProviderInput / 1MOutput / 1MUpdated
Microsoft Azure logo
Microsoft Azure
$0.250$2.003/31/2026
OpenRouter logo
OpenRouter
$1.25$10.004/14/2026

Prices updated daily. Last check: 4/14/2026

Model Details

General

Creator
OpenAI
Family
GPT
Tier
Flagship
Context Window
256K
Knowledge Cutoff
Mar 2025
Modalities
Text, Image

Capabilities

Tool Calling
Yes
Open Source
No
Subtypes
Chat Completion, Code Generation

Strengths & Limitations

  • 256K token context window enables processing of lengthy documents and conversations
  • Multimodal capabilities support both text and image inputs in a single interface
  • Tool calling functionality allows integration with external APIs and services
  • March 2025 knowledge cutoff provides relatively recent training data
  • Flagship tier positioning within OpenAI's model lineup for complex tasks
  • Specialized support for code generation alongside general chat completion
  • Extended context handling suitable for document analysis and long-form reasoning
  • Proprietary model with no open-source weights available
  • Limited to text and image modalities, no audio or video support
  • Requires API access rather than local deployment options
  • Knowledge cutoff means no awareness of events after March 2025
  • Higher computational requirements typical of flagship-tier models

Key Features

•256K token context window
•Multimodal input support (text and images)
•Tool calling with external API integration
•Chat completion interface
•Code generation capabilities
•Streaming response support
•Structured output formatting
•Function calling with parallel execution

About GPT-5.1

GPT-5.1 is OpenAI's flagship large language model in the GPT family, representing the latest generation of the company's most capable AI system. As a flagship-tier model, it sits at the top of OpenAI's model hierarchy, designed for the most demanding applications requiring advanced reasoning capabilities. The model features a 256K token context window and supports both text and image inputs as a multimodal system. GPT-5.1 includes tool calling functionality and specializes in chat completion and code generation tasks. With a knowledge cutoff of March 2025, it incorporates relatively recent training data compared to older model generations. GPT-5.1 is typically deployed for complex applications requiring sophisticated reasoning, multimodal understanding, and extended context handling. As a proprietary model from OpenAI, it's available through API access rather than open-source distribution, positioning it for enterprise and developer use cases that demand high-capability AI assistance.

Common Use Cases

GPT-5.1 is designed for complex, high-stakes applications that require OpenAI's most capable reasoning abilities. Its 256K context window makes it well-suited for document analysis, legal review, research synthesis, and other tasks involving lengthy texts. The multimodal capabilities enable use cases combining text and visual information, such as technical documentation with diagrams, data visualization analysis, or educational content creation. As a flagship model with tool calling support, it's particularly effective for agentic workflows, complex coding projects, and enterprise applications requiring integration with external systems and APIs.

Frequently Asked Questions

How much does GPT-5.1 cost per million tokens?

GPT-5.1 pricing varies by provider and usage type (standard vs batch processing). Input and output tokens are typically priced differently. Check the pricing table above for current rates across all available providers.

What is GPT-5.1 best used for?

GPT-5.1 excels at complex reasoning tasks, document analysis with its 256K context window, multimodal applications combining text and images, advanced code generation, and agentic workflows using tool calling. It's designed for demanding use cases that require OpenAI's flagship-level capabilities.

How does GPT-5.1 compare to other flagship models like Claude Opus 4.6?

GPT-5.1 offers a 256K context window and multimodal text/image support, while specific benchmark comparisons depend on the task. Both are flagship-tier models with tool calling capabilities, but they may have different strengths in reasoning, coding, or creative tasks based on their training approaches and architectures.