Test: Claude Opus 5.5 is 56% cheaper than Opus 5 at equal prices

An independent test across 468 tasks found Claude Opus 5.5 writes 341 output tokens on average versus 799 for Opus 5, making it 56% cheaper at identical rates. In a multi-hop tool loop the gap narrows to 22% because input tokens dominate. Opus 5.5 launched on 2026-09-22 at $4/$20 per million tokens versus $5/$25 for Opus 5.

• Opus 5.5 costs $4 per million input and $20 per million output tokens vs $5/$25 for Opus 5
• Across 468 tasks Opus 5.5 billed $0.0072 per task against $0.0204 for Opus 5
• At equal prices Opus 5.5 is 56% cheaper: 341 vs 799 output tokens
• In a tool loop the saving drops to 22% as input tokens dominate