Comprehensive side-by-side LLM comparison
o3 leads with 28.7% higher average benchmark score. o3 offers 36.0K more tokens in context window than Claude Sonnet 4.5. o3 is $8.00 cheaper per million tokens. Overall, o3 is the stronger choice for coding tasks.
Anthropic
Claude Sonnet 4.5 is a multimodal language model developed by Anthropic. It achieves strong performance with an average score of 75.8% across 9 benchmarks. It excels particularly in MMMLU (89.1%), AIME 2025 (87.0%), TAU-bench Retail (86.2%). It supports a 264K token context window for handling large documents. The model is available through 2 API providers. As a multimodal model, it can process and understand text, images, and other input formats seamlessly. Released in 2025, it represents Anthropic's latest advancement in AI technology.
OpenAI
o3 is a multimodal language model developed by OpenAI. It achieves strong performance with an average score of 67.5% across 22 benchmarks. It excels particularly in COLLIE (98.4%), AIME 2024 (91.6%), ARC-AGI (88.0%). It supports a 300K token context window for handling large documents. The model is available through 1 API provider. As a multimodal model, it can process and understand text, images, and other input formats seamlessly. Released in 2025, it represents OpenAI's latest advancement in AI technology.
5 months newer
o3
OpenAI
2025-04-16
Claude Sonnet 4.5
Anthropic
2025-09-29
Cost per million tokens (USD)
Claude Sonnet 4.5
o3
Context window and performance specifications
Average performance across 28 common benchmarks
Claude Sonnet 4.5
o3
o3
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
Claude Sonnet 4.5
o3
o3
OpenAI