Anthropic has announced the launch of Claude Sonnet 4.5, the first model in its forthcoming Claude 4.5 family. This next-generation model raises the industry bar for intelligence, outperforming competitor models and Anthropic's previous top-tier model, Claude 3 Opus, on a wide range of evaluations. At the same time, it offers the speed and cost of the previous generation's mid-tier model, Claude 3 Sonnet.
Key Features and Performance Gains
Claude Sonnet 4.5 sets new industry benchmarks for graduate-level reasoning (GPQA), undergraduate-level knowledge (MMLU), and coding proficiency (HumanEval). The model operates at twice the speed of Claude 3 Opus , making it ideal for complex tasks such as context-sensitive customer support and orchestrating multi-step workflows. In an internal agentic coding evaluation, Claude Sonnet 4.5 solved 64% of problems, outperforming Claude 3 Opus which solved 38%. This improvement allows it to independently write, edit, and execute code with sophisticated reasoning.
Advanced Vision Capabilities
Claude Sonnet 4.5 is Anthropic's strongest vision model yet, surpassing Claude 3 Opus on standard vision benchmarks. These improvements are most noticeable for tasks requiring visual reasoning, like interpreting charts and graphs. The model can also accurately transcribe text from imperfect images , a core capability for retail, logistics, and financial services.
New Feature: Artifacts
A groundbreaking new feature introduced with Claude Sonnet 4.5 is "Artifacts." This feature allows users to see, edit, and build upon Claude's generated content in real-time in a separate window. For example, when a code snippet is requested, the code appears in the Artifacts window while the explanation remains in the chat. This creates an interactive workspace where users can iterate on their work directly within the Claude interface. The Artifacts feature is available to all Claude users, including free accounts, on both desktop and mobile.
Pricing and Availability
Claude Sonnet 4.5 is available for free on Claude.ai and the Claude iOS app , with Claude Pro and Team plan subscribers able to access it with significantly higher rate limits. It is also available via the Anthropic API, Amazon Bedrock, and Google Cloud's Vertex AI. The API pricing is competitive, costing $3 per million input tokens and $15 per million output tokens , and features a 200K token context window.
The Future of the Claude 4.5 Family
Anthropic plans to release the rest of the Claude 4.5 model family, Claude 4.5 Haiku and Claude 4.5 Opus, later this year. The company aims to substantially improve the tradeoff between intelligence, speed, and cost every few months. Additionally, Anthropic is developing new features like Memory, which will enable Claude to remember a user's preferences and interaction history for a more personalized experience.