Claude Opus vs Sonnet (2026)

Claude Opus and Sonnet are Anthropic's two primary models. Opus is the powerhouse; Sonnet balances speed and cost. Here's how to choose—and run both on your single unoblox API key.

Direct comparison

Aspect	Claude Opus (₹)	Claude Sonnet (₹)
Input price	₹504/M	₹201.6/M
Output price	₹2520/M	₹1008/M
Reasoning quality	Best-in-class	Excellent, 80% of Opus
Speed	Slightly slower	2–3x faster
Context window	200k	200k
Cost ratio	2.5x Sonnet	Baseline

When Opus is worth the premium

• Nuance-critical tasks: Legal review, medical advice, safety-sensitive content.
• Complex analysis: Long documents (reports, codebases, research papers).
• Creative work: Opus often outperforms Sonnet on poetry, storytelling, tone-matching.
• Instruction-following: When your prompt demands perfect adherence and minimal hallucination.

When Sonnet is the smart choice

• Chat and Q&A: Sonnet handles conversational tasks nearly as well as Opus.
• Coding: For code generation, Sonnet matches Opus in most scenarios.
• Summarization: Extracting key facts? Sonnet is fast and reliable.
• Cost-conscious scaling: 60% cost savings on a large user base adds up fast.
• Real-time applications: Lower latency for chatbots and live dashboards.

Cost scenario: annual spend

If your app processes 10 billion input tokens and 5 billion output tokens per year:

Model	Input cost	Output cost	Annual total
Claude Opus	₹50.4 lakh	₹1.26 crore	₹1.764 crore
Claude Sonnet	₹20.16 lakh	₹50.4 lakh	₹70.56 lakh
Difference	—	—	Save ₹1.0584 crore/year with Sonnet (~60%)

At scale, Sonnet is the economical default — reserve Opus for the slice of traffic where its extra nuance actually changes the outcome.

Frequently asked questions

Can I use Sonnet for everything and save money? For 80% of tasks, yes. Reserve Opus for nuance-critical work (legal, medical, brand voice).

Is it hard to switch between them? No. Identical API; only change the model name. We recommend A/B testing on your actual workload.

Does Opus have a longer context window? Both have 200k tokens. Opus's advantage is reasoning depth within that window, not capacity.

Should I always choose Sonnet for new features? Start with Sonnet for speed and cost. Upgrade to Opus if your users complain about quality. One API key makes this free to experiment.

Can I route users smartly between models? Yes. Use Sonnet for casual users, Opus for power users or paid tiers. Same endpoint, same code.

Is Opus's output noticeably better? On most tasks, no. On creative, nuanced, and safety-critical work, yes. Run a 100-case eval on your data to decide.

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