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OpenAI: GPT-5.3-Codex vs Anthropic: Claude Sonnet 4.6

Side-by-side comparison of specs, pricing, benchmark scores, and task rankings. Updated 2026-09-23.

OpenAI: GPT-5.3-Codex Anthropic: Claude Sonnet 4.6
Vendoropenaianthropic
Quality Score100100
Benchmark Score53.369.7
Input Price$1.75/M$3.00/M
Output Price$14.00/M$15.00/M
Context Window400,0001,000,000
Max Output128,000128,000
Tool Calling✓✓
Structured Output✓✓
Reasoning Mode✓✓
Vision✓✓
Audio--
Benchmark Scores
ai_index53.649.6
aider_polyglot-61.3
eqbench-80.0

Who wins by task?

TaskOpenAI: GPT-5.3-CodexAnthropic: Claude Sonnet 4.6
SQL Generation 138 154
Code Review 142 161
Code Completion 117 120
Code Refactoring 144 162
Bug Fixing 146 166
Unit Test Generation 130 144
Code Documentation 133 142
Regex Writing 122 129
CI/CD Pipelines 126 138
Frontend Component Design 128 137
Data Analysis 132 147
CSV / Spreadsheet Cleanup 134 145
ETL Scripting 135 150
JSON Extraction 120 125
Bulk Data Labeling 117 118
OCR / Document Parsing 133 140
Table Extraction from PDFs 133 140
Long-Document Summarization 145 161
Short-Form Summarization 115 118
Blog Post Writing 126 137

Scores reflect capability match + benchmark data + pricing for each task. Methodology →

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