How does Claude Sonnet 5 compare to Claude Opus 5 in capability and cost?

Both models share the same 1M token context window, 128k max output, and five-level effort framework (low/medium/high/xhigh/max, default high), but Opus 5 is priced meaningfully higher per token and generally scores higher on the hardest, longest-horizon reasoning and coding benchmarks.

Sonnet 5 is described as approaching Opus-class performance on many everyday coding and knowledge-work tasks, and on at least one major coding benchmark it has been reported to edge out Opus 4.8, but on the most demanding long-horizon benchmarks it trails both Opus 4.8 and Opus 5 by a wider margin.

The practical framing many teams land on is workload-based rather than purely benchmark-based: Sonnet 5 at low-to-medium effort for high-volume, well-scoped work, escalating to Opus 5 at high effort specifically when a task needs deeper reasoning, self-verification, or long-context judgment that Sonnet 5 struggles with even at its own higher effort settings.