AI: Anthropic Opus 4.5 vs Sonnet 4.5 model

Claude Opus 4.5 vs Sonnet 4.5 Review: Worth the Premium? (2025) - YouTube

Opus 4.5 offers significantly better performance on complex tasks, but Sonnet 4.5 is cheaper with lower API costs ($3/$15 per million input/output tokens) and is sufficient for most high-throughput applications. Opus 4.5 has a higher API cost ($5/$25 per million input/output tokens) but is also more token-efficient, meaning it uses fewer tokens to achieve similar or better results, potentially making it more cost-effective for certain workflows, especially when its "effort" parameter is used to lower costs.

Feature	Sonnet 4.5	Opus 4.5
API Price	$3 input / $15 output per million tokens	$5 input / $25 output per million tokens
Token Efficiency	Less efficient than Opus	More efficient, uses fewer tokens for comparable results
Best Use Case	High-throughput applications where speed matters	Complex tasks that require deeper reasoning
Cost Considerations	Lower base price, ideal for high volume when efficiency is less critical	Higher base price, but can be more cost-effective due to token efficiency and the "effort" parameter

Claude Sonnet 4.5 vs Opus 4.5: The Complete Comparison

Opus 4.5 solves problems with dramatically fewer steps—less backtracking, less redundant exploration, less verbose reasoning. At medium effort level, Opus 4.5 matches Sonnet 4.5's best SWE-bench score while using 76% fewer output tokens. At high effort, it exceeds Sonnet 4.5 by 4.3 percentage points while still using 48% fewer tokens.