+
+
+
+
+
+
+
+
VS
VS
VS
VS
VS
VS
GPT-5 Codex vs o3
Comprehensive side-by-side LLM comparison
GPT-5 Codex leads with 5.4% higher average benchmark score. o3 supports multimodal inputs. Overall, GPT-5 Codex is the stronger choice for coding tasks.
+
+
+
+
OpenAI
GPT-5 Codex was developed as a specialized variant of GPT-5 optimized for programming and software development tasks. Built to understand and generate code across multiple programming languages, it serves developers with enhanced capabilities for code completion, debugging, translation, and explanation of complex codebases.
+
+
+
+
OpenAI
o3 represents the next generation in OpenAI's reasoning model series, developed to advance the capabilities of deliberate, step-by-step problem solving. Built to handle increasingly complex challenges across mathematics, science, and coding, it continues the evolution of reasoning-focused AI with improved analytical depth and accuracy.
5 months newer
o3
OpenAI
2025-04-16
GPT-5 Codex
OpenAI
2025-09-15
+
+
+
+
+
+
+
+
+
+
+
+
Performance Metrics
Context window and performance specifications
Average performance across 1 common benchmarks
+
+
+
+
GPT-5 Codex
Average Score:74.5%(+5.4%)
+
+
+
+
o3
Average Score:69.1%
Performance comparison across key benchmark categories
+
+
+
+
GPT-5 Codex
Coding74.5%(+5.4%)
+
+
+
+
o3
Coding69.1%
+
+
+
+
Knowledge Cutoff
Training data recency comparison
o3
2024-05-31
GPT-5 Codex
2024-09-30
More recent knowledge cutoff means awareness of newer technologies and frameworks
Provider Availability & Performance
Available providers and their performance metrics
+
+
+
+
GPT-5 Codex
0 providers
+
+
+
+
o3
1 providers
OpenAI
Throughput:
+
+
+
+
GPT-5 Codex
Avg Score:74.5%(+5.4%)
Providers:0
+
+
+
+
o3
Avg Score:69.1%
Providers:1