Claude Sonnet 4.5 — reviews, specs & pricing

Anthropic's balanced flagship model for coding and agents.

Summary

Claude Sonnet 4.5 offers strong coding and agentic capabilities at a mid-tier price point, with a 200k context window (1M in beta). It's positioned as Anthropic's best model for real-world agentic tasks. It supports vision and extended thinking.

Sample use case

Used for coding assistants, autonomous agents, and everyday enterprise chat applications. Balances cost and capability for production use.

Specifications

  • Provider: anthropic
  • License: closed
  • Context: 200k tokens
  • Input price: $3/M tok
  • Output price: $15/M tok
  • Released: 2025-09-29

Pros

  • Strong coding performance
  • Good price/performance
  • Extended thinking mode

Cons

  • Closed weights
  • Not as strong as Opus on hardest tasks
  • Context limited vs some competitors

Average rating 0.0 from 0 community reviews on Reviuws.

Frequently asked questions

What is Claude Sonnet 4.5?

Claude Sonnet 4.5 offers strong coding and agentic capabilities at a mid-tier price point, with a 200k context window (1M in beta). It's positioned as Anthropic's best model for real-world agentic tasks. It supports vision and extended thinking.

How much does Claude Sonnet 4.5 cost?

Claude Sonnet 4.5 costs $3 per million input tokens and $15 per million output tokens.

Is Claude Sonnet 4.5 open source?

Claude Sonnet 4.5 is released under the closed license.