Comprehensive side-by-side LLM comparison
Claude Opus 4.5 leads with 7.5% higher average benchmark score. Claude Opus 4.5 supports multimodal inputs. Claude Opus 4.5 is available on 3 providers. Overall, Claude Opus 4.5 is the stronger choice for coding tasks.
Anthropic
Claude Opus 4.5, released by Anthropic in November 2025, is a large language model from the Claude 4.5 family built for demanding reasoning tasks, advanced code generation, and complex agentic workflows. It features a 200K token context window, 64K maximum output tokens, native image understanding, and extended thinking with configurable effort levels. Opus 4.5 targets deep analytical work, multi-step tool orchestration, and applications requiring sustained reasoning across long, complex tasks.
OpenAI
GPT-5 Codex, released by OpenAI in August 2025, is a coding-specialized large language model from the GPT-5 family engineered for software engineering, code generation, and agentic development workflows. It builds on GPT-5's architecture with optimizations targeting multi-file code editing, test generation, and automated debugging. GPT-5 Codex targets developers and agentic coding tools requiring a model tuned specifically for programming tasks.
3 months newer

GPT-5 Codex
OpenAI
2025-08

Claude Opus 4.5
Anthropic
2025-11-01
Context window and performance specifications
Average performance across 3 common benchmarks
Claude Opus 4.5
GPT-5 Codex
Performance comparison across key benchmark categories
Claude Opus 4.5
GPT-5 Codex
Claude Opus 4.5
2025-05
Available providers and their performance metrics
Claude Opus 4.5
Anthropic
AWS Bedrock
Google Cloud Vertex AI
GPT-5 Codex
Claude Opus 4.5
GPT-5 Codex
Claude Opus 4.5
GPT-5 Codex