Comprehensive side-by-side LLM comparison
o3-pro offers 36.0K more tokens in context window than Claude Sonnet 4.5. Claude Sonnet 4.5 is $82.00 cheaper per million tokens. Both models have their strengths depending on your specific coding needs.
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.
OpenAI
o3-pro was developed as the flagship reasoning model in the o3 family, designed to deliver maximum reasoning depth and reliability for the most challenging analytical tasks. Built for professionals requiring the highest level of thoughtful problem-solving, it extends reasoning capabilities to handle complex multi-step challenges across diverse domains.
3 months newer

o3-pro
OpenAI
2025-06-10

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

Claude Sonnet 4.5

o3-pro
Context window and performance specifications
o3-pro
2024-05-31
Claude Sonnet 4.5
2025-01-31
Available providers and their performance metrics

Claude Sonnet 4.5
Anthropic
ZeroEval


Claude Sonnet 4.5

o3-pro

Claude Sonnet 4.5

o3-pro
o3-pro
OpenAI