Claude Sonnet 4.6: Features, Benchmarks, Pricing and Guide
Anthropic released Claude Sonnet 4.6 on 17 February 2026, and within hours it became the default model on claude.ai. It represents a qualitative shift in the Sonnet line, offering frontier-level intelligence at a fraction of the cost.
The pitch is straightforward: performance that used to require paying the Opus premium is now available at the balanced Sonnet price point. For 90% of daily tasks, Sonnet 4.6 is now the optimal choice.
The 1M Token Context Window Comes to Sonnet
Like Opus 4.6, Sonnet 4.6 gets the massive 1M token context window. This allows users to feed the model entire document libraries or multi-file codebases.
Memory retrieval performance
On MRCR v2 (8 needles at 1M), Sonnet 4.6 scores 65% Mean Match Ratio—a 3.5x improvement over Sonnet 4.5's 18.5%. It makes long-context reasoning truly viable at scale.
Computer Use: Best-in-Class Automation
Anthropic's latest OSWorld benchmarks position Sonnet 4.6 as their strongest model for computer use. It excels at navigating complex spreadsheets, filling multi-step web forms, and cross-tab browser workflows.
Prompt Injection Resistance
Sonnet 4.6 matches Opus 4.6 in security, with a 99.38% refusal rate for malicious operational requests—critical for safe web-browsing agents.
Benchmarks: Closing the Gap
| Benchmark | Sonnet 4.6 | Opus 4.6 | GPT-5.2 |
|---|---|---|---|
| Sway Bench (Coding/Finance) | 79.6 | - | - |
| Instruction Following | Beats GPT-5.2 | - | Baseline |
| Latency per Quality | Best Ratio | Higher | Mixed |
When to Use Sonnet 4.6 vs Opus 4.6
Use Sonnet 4.6 for:
- • 90% of daily coding tasks
- • High-volume data processing
- • Web & Desktop automation agents
- • Routine knowledge work
Reserve Opus 4.6 for:
- • Complex, zero-error architecture
- • Extended 14h+ agentic sessions
- • Deep disciplinary research
- • High-stakes infrastructure logic
Pricing advantage: Sonnet 4.6 is roughly 1.7x cheaper per million tokens than Opus 4.6, with faster response times.
