Claude Opus 4.8 vs Sonnet 4.6: Which Should You Use? (2026)

Opus 4.8 costs $5 per million input tokens and $25 per million output tokens. Sonnet 4.6 costs $3 input and $15 output. Output is where the gap bites: at $25 vs $15 per million, a chatty, long-output workload on Opus can cost roughly 67% more per generated token than on Sonnet.

Both models include a 1M-token context window at standard pricing (Opus 4.6+ and Sonnet 4.6), so you're not paying a premium just to use long context. Both also support the same cost levers: the Batch API gives 50% off input and output for non-urgent jobs, and prompt caching drops cache-read (hit) tokens to roughly 10% of the base input price. Exact figures are on the Claude API pricing detail page.

Because the levers are identical, the decision comes down to one question: does the extra per-token cost of Opus buy you enough additional capability on this specific task to be worth it? For a lot of everyday work, it doesn't.

Opus 4.8 is Anthropic's most capable model, and that capability shows up most on tasks where a single wrong step compounds: complex multi-file refactors, dense technical reasoning, long agentic chains where the model has to plan and self-correct, and ambiguous problems where Sonnet tends to take the obvious-but-wrong path.

A useful heuristic: if you find yourself re-prompting Sonnet two or three times to fix the same class of mistake, the time you're burning (and the retry tokens) often justify just running Opus once. The most expensive model is the one you have to call five times.

Opus is also the safer default for high-stakes, one-shot outputs — a contract analysis, a migration plan, a security-sensitive code change — where you'd rather pay more than risk a subtle error.

Reach for Opus 4.8 when: the task is hard reasoning, complex/agentic coding, long multi-step planning, or a high-stakes one-shot output where errors are costly.
Stick with Sonnet 4.6 when: you're doing drafting, summarization, classification, straightforward code, chat, or high-volume work where speed and cost matter more than the last few points of capability.

Sonnet 4.6 is the right default for most production and everyday workloads. It's faster, which matters for interactive apps and anything user-facing, and at $3/$15 it's materially cheaper to run at scale. For content drafting, summarization, extraction, classification, customer-facing chat, and the bulk of code generation, the quality gap to Opus is small enough that most teams won't notice it on routine work.

At volume, the cost difference is the whole argument. If you're processing millions of tokens a day, the move from $25 to $15 output (plus Batch and caching) is the difference between a sustainable bill and a painful one. Many teams run Sonnet by default and route only the hardest requests to Opus.

If you mostly produce marketing, support, or social content, you'll get excellent results from Sonnet — pair it with our business email generator or blog post outline tool prompts.

You don't have to pick one. The cost-effective pattern is to default to Sonnet 4.6 and escalate to Opus 4.8 only on demand: when Sonnet's output fails a quality check, when a task is flagged high-stakes, or when a request needs deep multi-step reasoning. This captures most of Opus's upside while keeping the average cost close to Sonnet's.

Use Batch for anything that isn't latency-sensitive (50% off), and prompt caching for repeated system prompts or large shared context (cache hits run at roughly 10% of input price). These apply to both models, so they compound whichever you choose. See the pricing detail page for the current cache and batch math.