
Claude Opus 4 vs Sonnet 4: When to Use Each Model in 2026
Claude Opus 4 vs Sonnet 4 comes down to routing, not loyalty to one model. Use Sonnet 4 for most coding, documentation, support, and high-volume workflows; use Opus 4 when the task is ambiguous, multi-step, architecture-heavy, or expensive to get wrong. Quick Verdict: Should You Use Sonnet 4 or Opus 4? Claude Sonnet 4 is the default model for most production and developer workflows because it launched at $3 per million input tokens and $15 per million output tokens, while Claude Opus 4 launched at $15 and $75. That 5x price gap matters when a team runs code review, test generation, customer support, or internal chat hundreds of times per day. Opus 4 is the escalation model: use it for long-horizon planning, complex debugging, architecture review, research synthesis, and agentic coding where one better answer can save hours of engineering time. In Claude Code, this usually means starting a task with Sonnet and switching to Opus only when the model needs deeper reasoning, stronger persistence, or better recovery from failed attempts. The practical takeaway: Sonnet should handle the queue, Opus should handle the hard cases. ...








