LLM Price Watch

Claude Opus 4.8 vs Claude Sonnet 5: which do you actually need?

Claude Opus 4.8 costs 2.5x Claude Sonnet 5 on both input and output pricing — $5.00 vs $2.00 per million input tokens, $25.00 vs $10.00 per million output tokens. Same provider, same 1M context window, same tokenizer. At 100M input/30M output tokens a month, that's $1,250 for Opus versus $500 for Sonnet 5. The gap is purely about task complexity, not features.

Verified · pricing checked against Anthropic's own API documentation
ModelInput /1MOutput /1MContext
Claude Opus 4.8$5.00$25.001M tokens
Claude Sonnet 5$2.00*$10.00*1M tokens

* Sonnet 5 introductory rate through 31 Aug 2026. Standard rate from 1 Sep 2026: $3.00/$15.00 per 1M.

The output price gap

Output tokens are where the real cost divergence happens: Opus 4.8 charges 2.5x Sonnet 5's rate on output specifically, which matters most for workloads that generate long responses — reports, drafted content, extensive code. For input-heavy tasks like document analysis or classification, the gap is proportionally the same but the absolute dollar difference is smaller.

Worked example

At 100M input tokens and 30M output tokens a month — a realistic mid-size production workload — Opus 4.8 costs $1,250/month. Sonnet 5 costs $500/month at the current introductory rate (rising to $750/month after 1 September). That's a $750/month gap today, narrowing to $500/month once Sonnet 5's standard rate kicks in.

How we'd actually decide

Default to Sonnet 5. Reach for Opus 4.8 specifically when a task involves multi-step agentic reasoning, complex code review where mistakes are expensive to catch downstream, or genuinely difficult analysis where the extra capability measurably changes the output quality — not as a blanket "use the best model" policy. Most production workloads, including most coding assistance and content generation, don't need the premium.

Pricing verified 15 July 2026, non-cached list pricing. Use the calculator with your own volume for an exact estimate.

Frequently asked questions

How much more expensive is Claude Opus 4.8 than Claude Sonnet 5?

Opus 4.8 costs 2.5x Sonnet 5 on both input ($5.00 vs $2.00 per million tokens) and output ($25.00 vs $10.00). At a 100M input/30M output monthly workload, that's $1,250 for Opus versus $500 for Sonnet 5 — a $750 monthly gap.

Do Opus 4.8 and Sonnet 5 have the same context window?

Yes — both offer a 1M-token context window, so context size isn't the differentiator in this comparison. The decision comes down to task complexity and how much the extra reasoning capability is actually worth to your specific workload.

When is Opus 4.8 actually worth 2.5x the price of Sonnet 5?

On complex, high-stakes reasoning tasks — multi-step agentic workflows, difficult code review, or work where errors are expensive to catch later. For everyday writing, summarization, and most coding assistance, Sonnet 5 handles the task at a fraction of the cost with little practical difference in output quality.

Is Sonnet 5's price going to change soon?

Yes — Sonnet 5 is priced at $2.00/$10.00 per million tokens as an introductory rate through 31 August 2026, rising to $3.00/$15.00 from 1 September 2026. Even after that increase, it remains meaningfully cheaper than Opus 4.8's $5.00/$25.00.