Claude Opus and Claude Sonnet are Anthropic two main model tiers, with Opus as the premium flagship and Sonnet as the high-performance mid-tier. As of early 2026, Sonnet 4.6 delivers 98 percent of Opus coding performance at one-fifth the cost, making the choice between them one of the most common decisions developers face. 1)
| Dimension | Sonnet 4.6 | Opus 4.6 |
|---|---|---|
| Input price | $3 per 1M tokens | $15 per 1M tokens | |
| Output price | $15 per 1M tokens | $75 per 1M tokens | |
| Cost multiplier | 1x (baseline) | 5x |
| SWE-bench Verified (coding) | 79.6% | 80.8% |
| GPQA Diamond (PhD-level science) | 74.1% | 91.3% |
| OSWorld-Verified (computer use) | 72.5% | 72.7% |
| Standard context window | 200K tokens | 200K tokens |
| Extended context (beta) | Not available | 1M tokens |
| Agent Teams | Not available | Supported |
| Extended thinking | Not available | Supported |
| Response speed | Fast | Slower |
The coding gap between Sonnet and Opus has narrowed dramatically across versions. On SWE-bench Verified, Sonnet 4.6 scores 79.6 percent versus Opus 4.6 at 80.8 percent, a negligible 1.2-point difference. Sonnet 4.6 actually outperforms all prior Opus models on coding benchmarks. 3)
Sonnet is described as less lazy with cleaner code generation and better prompt adherence, and was preferred 59 to 70 percent over Opus 4.5 in developer tests. 4)
The biggest gap between the two models appears in expert-level reasoning. On GPQA Diamond, which tests PhD-level physics, chemistry, and biology, Opus 4.6 scores 91.3 percent versus Sonnet at 74.1 percent, a massive 17.2-point difference. 5)
Opus also leads on Terminal-Bench 2.0 (65.4 percent vs approximately 59 percent) and ARC-AGI-2 (approximately 68.8 percent vs 60.4 percent), demonstrating its edge in novel reasoning and long-context terminal tasks. 6)
Opus 4.6 offers several capabilities not available in Sonnet:
The gap between Sonnet and Opus has narrowed consistently across generations:
| Generation | Sonnet SWE-bench | Opus SWE-bench | Gap |
|---|---|---|---|
| Claude 4.5 | 77.2% | 80.9% | 3.7 points |
| Claude 4.6 | 79.6% | 80.8% | 1.2 points |
This trend reflects Anthropic strategy of pushing Sonnet capabilities upward while reserving exclusive features for Opus. 8)
Choose Sonnet 4.6 (80 to 90 percent of scenarios):
Choose Opus 4.6 (premium scenarios):
Sonnet 4.6 delivers 95 to 99 percent of Opus quality at 3 to 5x lower cost with a speed advantage, making it the recommended default for the vast majority of use cases. 10)