Opus 4.8 vs Sonnet 4.6: The Practical GA Choice

Comparisons informational Last reviewed Updated
Side-by-side: Opus 4.8 vs Sonnet 4.6. Figures sourced; unofficial numbers flagged.
Spec Claude Opus 4.8Claude Sonnet 4.6
Tier Opus Sonnet
Availability (general) Available Available
Context window 1M tokens unofficial
Max output Up to 64k tokens unofficial
Input price (per M tokens) $5 / M $3 / M
Output price (per M tokens) $25 / M $15 / M
How to access Claude API, apps, cloud marketplaces

The decision most users really face

With Mythos-class editions gated and suspended, the practical flagship choice is Opus 4.8 versus Sonnet 4.6 — both generally available. Opus 4.8 is the top-tier GA model at $5/$25 per million; Sonnet 4.6 is the balanced tier at $3/$15, faster and cheaper.

Pick on workload, not prestige

Sonnet 4.6 handles the large majority of production tasks well: drafting, summarization, extraction, routine coding, and chat. Opus 4.8 earns its premium on the hard end — complex multi-step reasoning, intricate code, nuanced analysis, and long agentic chains where quality compounds. The economical pattern is to run Sonnet 4.6 by default and route only the genuinely difficult cases to Opus 4.8.

Cost math

Opus 4.8 is roughly 1.7x Sonnet's price on both input and output. If a workload is high-volume and well within Sonnet's ceiling, staying on Sonnet can cut spend substantially with little quality loss.

Caveat

Treat any circulating Opus-vs-Sonnet benchmark as unofficial. The reliable way to choose is to test both on your own representative prompts.

Frequently asked questions

Should I default to Opus 4.8 or Sonnet 4.6?

Default to Sonnet 4.6 for cost and speed, then escalate to Opus 4.8 only when a task clearly needs more reasoning power. Most workloads run fine on Sonnet.

How much more does Opus 4.8 cost?

Opus 4.8 is $5/$25 per million versus Sonnet 4.6's $3/$15 — roughly 1.7x on both input and output.

Are these affected by the Mythos suspension?

No. Opus 4.8 and Sonnet 4.6 are generally available. The suspension applies to Fable 5 and Mythos 5.

Sources & further reading

Facts on this page link to their source. Quotes are kept under 15 words and attributed; figures labelled unofficial are third-party until Anthropic publishes system-card numbers.