Comprehensive side-by-side LLM comparison
Claude Sonnet 4.5 leads with 6.6% higher average benchmark score. Claude Opus 4 offers 64.0K more tokens in context window than Claude Sonnet 4.5. Claude Sonnet 4.5 is $72.00 cheaper per million tokens. Claude Opus 4 is available on 4 providers. Overall, Claude Sonnet 4.5 is the stronger choice for coding tasks.
Anthropic
Claude Opus 4 was developed as the flagship model in the Claude 4 generation, designed to push the boundaries of AI capability in complex reasoning, analysis, and multi-step problem-solving. Built to handle the most demanding enterprise tasks, it represents Anthropic's highest tier of intelligence and capability.
Anthropic
Claude Sonnet 4.5 was developed to bridge human thinking and machine assistance, allowing people to work with language and tools in a more conversational and natural way. Built with a focus on turning ideas into results, it represents an evolution in making AI feel less mechanical while maintaining strong capabilities across reasoning, coding, and collaborative tasks.
4 months newer

Claude Opus 4
Anthropic
2025-05-22

Claude Sonnet 4.5
Anthropic
2025-09-29
Cost per million tokens (USD)

Claude Opus 4

Claude Sonnet 4.5
Context window and performance specifications
Average performance across 7 common benchmarks

Claude Opus 4

Claude Sonnet 4.5
Performance comparison across key benchmark categories

Claude Opus 4

Claude Sonnet 4.5
Claude Sonnet 4.5
2025-01-31
Available providers and their performance metrics

Claude Opus 4
Anthropic
Bedrock
ZeroEval

Claude Opus 4

Claude Sonnet 4.5

Claude Opus 4

Claude Sonnet 4.5

Claude Sonnet 4.5
Anthropic
ZeroEval