Is Claude Sonnet 4.5 free?

Claude Sonnet 4.5 is available on the free tier of Claude.ai, but with lower usage limits. For higher limits and priority access, a Pro subscription ($17/month) or Max subscription ($100/month) is required.

What is the difference between Sonnet 4.5 and Opus 4.5?

Sonnet 4.5 is optimized for speed and agentic tasks like coding and computer control, while Opus 4.5 is the larger, more expensive "reasoning" model designed for the absolute highest intelligence on open-ended problems and deep research.

Can Claude Sonnet 4.5 use my computer?

Yes, it features advanced "Computer Use" capabilities that allow it to navigate web browsers, click buttons, and type text to automate repetitive workflows, which is significantly improved over the beta version in Sonnet 3.5.

How much does the API cost?

The API pricing for Claude Sonnet 4.5 is $3.00 per million input tokens and $15.00 per million output tokens, which is the same as the previous Sonnet 4 model.

Claude Sonnet 4.5

The best model in the world for agents, coding, and computer use.

From Anthropic

Founder: Dario Amodei, Daniela Amodei, Jared Kaplan, Jack Clark, Ben Mann

Text Generator

29 Sep 2025

30 Million+

Freemium

Pricing Model

Freemium

Starting Price

$17/Month

About This AI

Claude Sonnet 4.5 is Anthropic’s flagship “frontier” model designed specifically for complex agentic workflows, software engineering, and autonomous computer use.

Released in late 2025, it represents a significant leap over Sonnet 4, capable of maintaining focus on tasks for over 30 hours and executing multi-step coding projects with near-human reliability.

It introduces the “Claude Agent SDK,” allowing developers to build long-running agents that can navigate browsers, edit files, and self-correct errors better than any previous model.

AI App Builder AI Website Builder Chatbot Coding Conversation LLM

Pricing

Pricing Model

Freemium

Starting Price

$17/Month

Key Features

Agentic Coding: Capable of handling the entire software development lifecycle, from planning to refactoring, with a native VS Code extension.
Computer Use: excels at controlling computers to automate browser-based tasks like research, procurement, and data entry with high reliability.
Claude Agent SDK: A dedicated framework for building autonomous agents with memory, permissions, and sub-agent coordination.
Checkpoints: Allows developers to save progress and "roll back" to previous states during complex coding sessions.
Extended Context: Supports up to 200K tokens standard, with a 1M token context window available in beta for deep analysis.
Safety Level 3 (ASL-3): Built with advanced safeguards against misuse in cybersecurity and other sensitive domains.

Pros

Highest score on SWE-bench Verified (82.0%), beating all competitors in coding.
Exceptional at long-horizon tasks requiring sustained focus.
"Checkpoints" feature saves massive amounts of time in development.
Native computer control is more robust than in Sonnet 3.5.
Cost-effective pricing compared to the larger Opus 4.5 model.

Cons

Rate limits can still be a friction point for heavy API users.
Very high usage requires the expensive "Max" subscription ($100/mo).
"Computer Use" can still face latency issues in real-time interactions.
Strict safety filters may occasionally refuse benign but complex prompts.

Best for Software engineers, data scientists, and enterprises building autonomous AI agents that need to interact with computers, write complex code, and manage long-running workflows.

FAQs

Is Claude Sonnet 4.5 free?
Claude Sonnet 4.5 is available on the free tier of Claude.ai, but with lower usage limits. For higher limits and priority access, a Pro subscription ($17/month) or Max subscription ($100/month) is required.
What is the difference between Sonnet 4.5 and Opus 4.5?
Sonnet 4.5 is optimized for speed and agentic tasks like coding and computer control, while Opus 4.5 is the larger, more expensive “reasoning” model designed for the absolute highest intelligence on open-ended problems and deep research.
Can Claude Sonnet 4.5 use my computer?
Yes, it features advanced “Computer Use” capabilities that allow it to navigate web browsers, click buttons, and type text to automate repetitive workflows, which is significantly improved over the beta version in Sonnet 3.5.
How much does the API cost?
The API pricing for Claude Sonnet 4.5 is $3.00 per million input tokens and $15.00 per million output tokens, which is the same as the previous Sonnet 4 model.