Claude Sonnet 4.5
Summary
Claude Sonnet 4.5 is Anthropic's latest frontier AI model, designed to excel in coding, complex reasoning, agentic tasks, and computer use.
Claude Sonnet 4.5 is a large language model from Anthropic with particular strengths in software coding, agentic tasks where it runs in a loop and uses tools, and in using computers. The model maintains focus for more than 30 hours on complex, multi-step tasks. Pricing remains the same as Claude Sonnet 4, at $3/$15 per million tokens. It is the most aligned frontier model Anthropic has released, showing large improvements across several areas of alignment compared to previous Claude models.
Bottom line: Claude Sonnet 4.5 shows state-of-the-art performance on benchmarks such as SWE-bench Verified and OSWorld.
Pricing Plans
SubscriptionLast verified 2 months ago- Price
- $20/mo
- Free Tier
- Chat on web, iOS, Android, and on your desktop. Generate code and visualize data. Write, edit, and create content. Ability to search the web. Memory across conversations. Create files and execute code. Unlock more from Claude with desktop extensions. Connect Slack and Google Workspace services. Integrate any context or tool through connectors with remote MCP. Extended thinking for complex work.
Free
Free for everyone
- Chat on web, iOS, Android, and on your desktop
- Generate code and visualize data
- Write, edit, and create content
- Ability to search the web
- Memory across conversations
- Create files and execute code
- Desktop extensions
- Connect Slack and Google Workspace services
- Integrate any context or tool through connectors with remote MCP
- Extended thinking for complex work
Pro
For everyday productivity. $17 per month with annual subscription discount ($200 billed up front). $20 if billed monthly.
- Everything in Free, plus
- More usage
- Includes Claude Code
- Includes Claude Cowork
- Access to unlimited projects to organize chats and documents
- Access to Research
- Ability to use more Claude models
- Claude for Microsoft 365
- Claude for Microsoft Outlook
Max
Get the most out of Claude. From $100 per month.
- Everything in Pro, plus
- Choose 5x or 20x more usage than Pro
- Higher output limits for all tasks
- Early access to advanced Claude features
- Priority access at high traffic times
View full pricing on anthropic.com →
Pricing may have changed since last verified. Check the official site for current plans.
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LLM Spec Sheet
Benchmarks
Pricing & Limits
- Input price
- $3.00 / 1M tokens
- Output price
- $15.00 / 1M tokens
- Max output tokens
- 64,000
Metrics from vendor, updated .
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Changelog
Pros
Sign in to edit- State-of-the-art on SWE-bench Verified evaluation for software coding abilities.
- Significant leap forward on computer use, leading at 61.4% on OSWorld benchmark.
- Most aligned frontier model with reduced concerning behaviors like sycophancy, deception, and power-seeking.
- Can maintain focus for more than 30 hours on complex multi-step tasks.
Cons
Sign in to edit- Context window limited to 200K tokens; 1M context beta was deprecated by Anthropic on April 30th 2026.
- Maximum output capacity of 64K tokens is lower than some competing models.
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About
- Platforms
- Claude API (claude-sonnet-4-5), Claude.ai web interface, iOS and Android apps, Amazon Bedrock, Google Cloud Vertex AI
- Languages
- Supports input and output in multiple languages
- API Available
- Yes
- Self-Hosted
- No
- Last Updated
- 2026-05-15T22:04:57.543Z
Best For
Who it's for
- Coding and software engineering tasks
- Long-running agentic workflows
- Complex multi-step reasoning
- Domain-specific analysis (finance, law, medicine)
- Browser automation and computer use
What it does well
- Software development and coding tasks
- Building autonomous agents
- Computer automation and browser use
- Financial analysis and research
- Code generation and debugging
Integrations
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Frequently Asked Questions
- Is Claude Sonnet 4.5 free?
- Claude Sonnet 4.5 has a permanent free tier alongside paid upgrades (paid plans from $20/mo). You can keep using a baseline version indefinitely without paying.
- Is Claude Sonnet 4.5 open source?
- No — Claude Sonnet 4.5 is a closed-source tool. Source code is not publicly available.
- Does Claude Sonnet 4.5 have an API?
- Yes. Claude Sonnet 4.5 exposes a developer API. See the official documentation at https://anthropic.com for details.
- When was Claude Sonnet 4.5 released?
- Claude Sonnet 4.5 was first released in 2025.
- What platforms does Claude Sonnet 4.5 support?
- Claude Sonnet 4.5 is available on: Claude API (claude-sonnet-4-5), Claude.ai web interface, iOS and Android apps, Amazon Bedrock, Google Cloud Vertex AI.
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Claude Sonnet 4.5 is a large language model from Anthropic with particular strengths in software coding, agentic tasks where it runs in a loop and uses tools, and in using computers. It has substantial capability improvements compared to previous Anthropic models on evaluations in areas such as reasoning and mathematics. The model maintains focus for more than 30 hours on complex, multi-step tasks. It is ideal for software development, domain-specific analysis in fields like finance, law, medicine, and STEM, and building intelligent agents.