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FlagshipAnthropic
Claude Sonnet 4.5
Claude Sonnet 4.5 is Anthropic's flagship multimodal model with text and image capabilities, featuring a 200K token context window and advanced reasoning abilities.
Context 200K
Tier Flagship
Knowledge Jan 2025
Tools Supported
Modalities text, image
Input from
$1.50 / 1M tokens
across 4 providers
API Pricing
Cheapest on Anthropic — 38% below avg| Provider | Input / 1M | Output / 1M | Cached / 1M |
|---|---|---|---|
| $1.50 | $7.50 | $0.150 | |
| $1.50 | $7.50 | $0.150 | |
| $1.65 | $8.25 | - | |
| $3.00 | $15.00 | $0.300 | |
| $3.00 | $15.00 | $0.300 | |
| $3.00 | $15.00 | $0.300 | |
| $3.30 | $16.50 | - |
Prices updated daily. Last check: Sep 6, 2026
Claude Sonnet 4.5 pricing by provider
Input, output, and batch rates, plus alternatives, for one provider at a time.
Performance & Benchmarks
Source: Artificial Analysis →Intelligence
22.7 / 100
Math
37.0 / 100
Reasoning & Knowledge
- MMLU-Pro86.0%
- GPQA Diamond72.7%
- Humanity's Last Exam7.2%
Coding
- LiveCodeBench59.0%
Math
- AIME 202537.0%
Agentic & Tool Use
- Terminal-Bench Hard28.8%
- τ²-bench70.5%
Instruction & Long Context
- IFBench42.7%
- Long-Context Reasoning54.0%
Benchmarks measured Sep 2026. Scores are independent evaluations, not vendor-reported.
Model Details
General
- Creator
- Anthropic
- Family
- Sonnet
- Tier
- Flagship
- Context Window
- 200K
- Knowledge Cutoff
- Jan 2025
- Modalities
- Text, Image
Capabilities
- Tool Calling
- Yes
- Open Source
- No
- Subtypes
- Chat Completion, Code Generation
- Aliases
- claude-sonnet-4-6
Strengths & Limitations
Strengths
- 200K token context window supports extensive document processing
- Multimodal capabilities handle both text and image inputs
- Tool calling functionality enables structured interactions and function execution
- Knowledge cutoff of January 1, 2025 provides relatively current information
- Chat completion and code generation specialized capabilities
- Flagship-tier model delivers Anthropic's most advanced reasoning abilities
- Support for complex visual understanding and analysis tasks
Limitations
- Proprietary model with no open-source weights available
- Limited to text and image modalities without audio or video support
- Higher computational requirements typical of flagship-tier models
- API-only access restricts deployment flexibility compared to open models
Key Features
•200K token context window
•Text and image input processing
•Tool calling with structured output
•Chat completion interface
•Code generation capabilities
•Streaming response support
•Multimodal reasoning and analysis
•Function execution integration
About Claude Sonnet 4.5
Claude Sonnet 4.5 is Anthropic's flagship model in the Sonnet family, representing the company's most capable offering for complex reasoning and multimodal tasks. As a proprietary model developed by Anthropic, it sits at the top tier of the Claude model lineup, designed for demanding applications that require sophisticated understanding and generation capabilities.
The model supports both text and image inputs with a 200K token context window, enabling processing of lengthy documents and detailed visual content. It includes tool calling functionality and maintains a knowledge cutoff of January 1, 2025. The model excels at chat completion and code generation tasks, handling complex conversations and programming challenges with multimodal understanding.
Claude Sonnet 4.5 competes directly with other flagship models like GPT-5.4 and Gemini 3.1 Pro in the current landscape. Organizations typically deploy it for applications requiring the highest level of reasoning capability, complex document analysis with visual elements, and sophisticated coding assistance where accuracy and context retention are critical.
Common Use Cases
Claude Sonnet 4.5 is designed for complex, high-stakes applications that demand flagship-level performance. Its multimodal capabilities make it well-suited for document analysis involving charts, diagrams, and visual elements, while the 200K context window enables comprehensive review of lengthy contracts, research papers, and codebases. Organizations deploy it for sophisticated coding assistance, complex reasoning tasks, advanced chatbots requiring nuanced understanding, and agentic workflows where tool calling enables integration with external systems. The model's flagship positioning makes it appropriate for scenarios where accuracy and capability are prioritized over cost considerations.
Frequently Asked Questions
How much does Claude Sonnet 4.5 cost per million tokens?
Claude Sonnet 4.5 pricing varies by provider and pricing type (standard vs batch). Check the pricing table above for current rates across all providers.
What is Claude Sonnet 4.5 best used for?
Claude Sonnet 4.5 excels at complex reasoning tasks, multimodal document analysis, sophisticated code generation, and applications requiring tool calling capabilities. Its 200K context window and flagship-tier performance make it ideal for demanding workflows involving lengthy documents with visual elements, advanced programming assistance, and complex agentic applications.
How does Claude Sonnet 4.5 compare to other flagship models?
Claude Sonnet 4.5 competes with models like GPT-5.4 and Gemini 3.1 Pro in the flagship tier. It offers multimodal text and image processing with a 200K token context window, tool calling capabilities, and Anthropic's constitutional AI approach. The choice between flagship models often depends on specific use case requirements, integration preferences, and performance characteristics for particular task types.