Claude Sonnet 4.6 vs Opus 4.6: Which One Should You Use?

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2026-02-27 | Model Review

Claude Sonnet 4.6 vs Claude Opus 4.6 — Who Wins?

Anthropic dropped two heavyweights in early 2026: Claude Opus 4.6* (February 4) and **Claude Sonnet 4.6 (February 17). On paper, Opus is the bigger brain and Sonnet is the faster, cheaper sibling. But the real picture is far more nuanced — Sonnet 4.6 punches so far above its weight that it actually *beats Opus in several categories.
We ran the numbers across every major benchmark so you don't have to. Here is the definitive breakdown.
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💰 Pricing — Sonnet Is 5x Cheaper

💻 Coding — Near-Identical, With a Twist

This is the category where the gap between the two models is shockingly small.

SWE-bench Verified (Real-World Bug Fixing)

| Model | Score | | :--- | :---: | | Opus 4.6 | 80.8% | | Sonnet 4.6 | 79.6% |
A difference of only 1.2 percentage points. For the vast majority of day-to-day coding — writing features, fixing bugs, refactoring — Sonnet 4.6 is essentially interchangeable with Opus.

Terminal-Bench 2.0 (Complex Agentic Coding)

| Model | Score | | :--- | :---: | | Opus 4.6 | 65.4% | | Sonnet 4.6 | 59.1% |
Winner: Opus 4.6. When the task involves navigating large multi-directory codebases, running multi-step terminal commands, and autonomously debugging — Opus still has a clear edge. This is where its deeper reasoning pays dividends.
The Verdict: Use Sonnet 4.6 as your daily coding companion. Reserve Opus 4.6 for large-scale refactors and complex agentic workflows where every percentage point counts.
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🧠 Deep Reasoning — Opus Dominates

This is where Opus 4.6 justifies its premium price tag.

GPQA Diamond (PhD-Level Science)

| Model | Score | | :--- | :---: | | Opus 4.6 | 91.3% | | Sonnet 4.6 | 74.1% |
A 17-point gap. On graduate-level physics, chemistry, and biology questions, Opus 4.6 operates on a fundamentally different level. If you're doing serious research, Opus is the only choice.

Humanity's Last Exam (HLE)

| Model | Score | | :--- | :---: | | Opus 4.6 (with tools) | 53.1% | | Opus 4.6 (no tools) | 40.0% |
This is the hardest public reasoning benchmark in existence — a multidisciplinary gauntlet designed to stump frontier models. Opus 4.6 leads the pack. Sonnet 4.6 doesn't have a publicly reported HLE score, which tells its own story.

MRCR V2 (Long-Context Needle-in-Haystack)

| Model | Score | | :--- | :---: | | Opus 4.6 | 76.0% | | Sonnet 4.5 | 18.5% |
Opus 4.6 retains information across its massive 1M-token context window with over 4x greater accuracy than the previous Sonnet generation. When you need to ingest a full codebase or seven novels at once and still find a specific detail, Opus is unmatched.
The Verdict: For anything involving deep scientific research, multi-step logical reasoning, or extreme context retention, Opus 4.6 is worth every penny.
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📊 Office & Finance — Sonnet Fights Back

Here's the surprise: Sonnet 4.6 actually outperforms Opus in real-world business tasks.

GDPVal-AA (Economically Valuable Knowledge Work)

| Model | Elo | | :--- | :---: | | Sonnet 4.6 | 1633 | | Opus 4.6 | 1606 |
Winner: Sonnet 4.6. On tasks that mirror actual professional work — financial analysis, legal research, business strategy — Sonnet delivers better results.

Agentic Financial Analysis

| Model | Score | | :--- | :---: | | Sonnet 4.6 | 63.3% | | Opus 4.6 | — |
Sonnet 4.6 leads the entire field in financial agent benchmarks, showcasing its real-world utility beyond synthetic tests.
The Verdict: If your use case is business automation, data analysis, or office productivity, Sonnet 4.6 is the better — and cheaper — choice.
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🖥️ Computer Use & Agentic Tasks — Dead Even

Both models are neck-and-neck in autonomous computer operation.

OSWorld-Verified (Autonomous Computer Tasks)

| Model | Score | | :--- | :---: | | Opus 4.6 | 72.7% | | Sonnet 4.6 | 72.5% |
A difference of 0.2%. For tasks like navigating applications, filling out forms, and completing multi-step computer workflows, both models perform almost identically. There is zero reason to pay the Opus premium here.
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⚡ Speed & Latency — Sonnet Runs Circles

Sonnet 4.6 is built for speed. It delivers responses at approximately 43–45 tokens per second* with latencies around *1.1–1.4 seconds for initial responses.
Opus 4.6, with its deeper reasoning chains, inherently takes longer. Its "Adaptive Thinking" architecture — which pauses to self-correct and allocate extra compute to hard sub-problems — is powerful, but it comes at a latency cost.
The Verdict: For real-time applications, chatbots, interactive tools, and batch processing, Sonnet 4.6's speed advantage is decisive.
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✍️ Creative Writing — Opus Has More Depth

For creative professionals, Opus 4.6 remains the superior model. Its deeper reasoning translates to:
* More nuanced character development — It tracks motivations, arcs, and emotional subtext across long narratives. * Better structural planning — It can outline novels, evaluate writing quality, and suggest improvements at a professional editor's level. * Superior role-play and dialogue — Community feedback consistently rates Opus higher for immersive, character-consistent responses.
Sonnet 4.6 is perfectly capable for blog posts, marketing copy, and standard content. But for long-form fiction, screenwriting, or any task that demands genuine creative depth, Opus is the model to reach for.
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The Head-to-Head Scorecard

Our Recommendation

Most teams should adopt a hybrid strategy:
1. Default to Sonnet 4.6 for 90% of tasks — coding, content, business analysis, customer-facing applications. It's fast, cheap, and remarkably close to Opus quality. 2. Escalate to Opus 4.6 when you hit a task that demands deep reasoning: scientific research, complex multi-step problem solving, large codebase refactors, or long-form creative work. 3. Use both with an effort parameter. Both models support Anthropic's new effort parameter, letting you dial quality vs. speed on a per-request basis.
The era of paying top dollar for everything is over. Sonnet 4.6 is the best value in frontier AI right now, and Opus 4.6 is the sharpest scalpel when you need one.
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Both Claude Sonnet 4.6 and Opus 4.6 are available on MangoMind — try them side-by-side and see the difference yourself.