Claude Sonnet 5.5 vs Opus 5.5: 42% cheaper and perfect on every run

Anthropic launched Claude Sonnet 5.5 six days after Opus 5.5. In The New Stack's testing, Sonnet 5.5 passed all 15 runs while Opus 5.5 passed 13, and cost $12.69 versus $22.07 — 42% less. At $2/$10 per million input/output tokens against Opus 5.5's $4/$20, Sonnet 5.5 uses more tokens, so real savings came to about 36%.

• Sonnet 5.5 scores 70.6% on Terminal-Bench 4.0 vs Opus 5.5's 66.4%
• Sonnet 5.5 costs $2/$10 per million tokens, half of Opus 5.5
• Sonnet 5.5 passed 15 of 15 runs; Opus 5.5 passed 13 of 15
• Sonnet 5.5 cost $12.69 vs Opus 5.5's $22.07 across all tests